Illustrative Math Alignment: Grade 8 Unit 3

Video Tutorial: Two-Step Equations: Multiplication and Subtraction. In this video, we will solve a two-step equation that involves multiplication and subtraction.

Topic

Equations

Definition

The "Not Equal To" symbol (≠) is used to indicate that two values are not equal.

Description

The "Not Equal To" symbol is crucial in mathematics as it denotes inequality between two expressions. This symbol is used in various mathematical contexts, such as solving inequalities, comparing numbers, and expressing conditions in algebraic equations. For example, in the inequality 𝑥 ≠ 5, it means that x can be any number except 5.

Topic

Equations

Definition

The Addition Property of Equality states that if you add the same value to both sides of an equation, the equality remains true.

Description

The Addition Property of Equality is a fundamental principle in algebra. It asserts that for any real numbers a, b, and c, if a = b, then a + c = b + c. This property is used to solve equations and maintain balance. For example, to solve x − 3 = 7, you add 3 to both sides to get x = 10.

Topic

Equations

Definition

An algebraic equation is a mathematical statement that shows the equality of two algebraic expressions. It's also another way of referring to a polynomial equation.

Description

Algebraic equations are central to algebra and involve variables, constants, and arithmetic operations. They are used to represent relationships and solve problems. For instance, the equation 2x + 3 = 7 can be solved to find x. Algebraic equations come in various forms, including linear, quadratic, and polynomial equations.

Topic

Equations

Definition

An algebraic expression is a combination of variables, constants, and arithmetic operations, without an equality sign.

Description

Algebraic expressions are fundamental components of algebra. They represent quantities and relationships without asserting equality. Examples include 3x + 4 and 5y − 2. Unlike equations, expressions cannot be solved but can be simplified or evaluated for given variable values.

Topic

Equations

Definition

Assigning values to variables involves giving specific values to variables in an equation or expression.

Description

Assigning values to variables is a fundamental process in algebra. It involves substituting variables with specific numbers to evaluate expressions or solve equations. For example, in the equation 

y = 2x + 3

assigning x = 4 gives y = 11.

Topic

Equations

Definition

A conditional equation is true only for specific values of the variable(s).

Description

Conditional equations are equations that hold true only under certain conditions or for specific variable values. For example, the equation 

x2 = 4 

is true only when x = 2 or x = −2. These equations contrast with identities, which are true for all variable values.

Topic

Equations

Definition

A constant term is a term in an algebraic expression that does not contain any variables.

Description

Constant terms are fixed values in algebraic expressions and equations. They do not change because they lack variables. For example, in the expression 

3x + 4

the number 4 is a constant term. Constant terms are essential in forming and solving equations.

Topic

Equations

Definition

The Division Property of Equality states that if you divide both sides of an equation by the same nonzero value, the equality remains true.

Description

The Division Property of Equality is a key principle in algebra. It states that for any real numbers a, b, and c (where 𝑐 ≠ 0), if 

a = b, then a ÷ c​ = b ÷ c 

This property is used to solve equations by isolating variables. For example, to solve 

3x = 12

divide both sides by 3 to get x = 4.

Topic

Equations

Definition

Equality is a mathematical statement that asserts that two expressions are equal.

Description

Equality is a foundational concept in mathematics. It indicates that two expressions have the same value, represented by the symbol "=". For example, in the equation 2 + 3 = 5, both sides are equal. Equality is used to form equations and solve problems.

In real-world applications, equality is used in accounting, engineering, and data analysis to ensure balance and accuracy. Understanding equality helps students develop logical reasoning and problem-solving skills.

Topic

Equations

Definition

An equation is a mathematical statement that asserts the equality of two expressions.

Description

Equations are central to mathematics, representing relationships between quantities. They consist of two expressions separated by an equals sign. For example, 

2x + 3 = 7

is an equation that can be solved to find x. Equations can be linear, quadratic, or polynomial, among others.

Topic

Equations

Definition

Equations in one variable involve a single variable and can be solved to find its value.

Description

Equations in one variable are fundamental in algebra. They typically take the form of ax + b = 0, where x is the variable. Solving these equations involves isolating the variable to determine its value. For example, solving 

2x + 3 = 7 

yields 

x = 2

Topic

Equations

Definition

Equations in two variables involve two variables and describe a relationship between them.

Description

Equations in two variables are essential in algebra and coordinate geometry. They typically take the form of 

ax + by = c

and represent lines in a coordinate plane. For example, the equation 

2x + 3y = 6

can be graphed as a line.

Topic

Equations

Definition

Equivalent equations are equations that have the same solutions.

Description

Equivalent equations are a key concept in algebra. They may look different but yield the same solutions. For instance, 

2x + 3 = 7

and 

4x + 6 = 14

are equivalent because both have the solution x = 2. Transformations such as addition, subtraction, multiplication, or division can produce equivalent equations.

Topic

Equations

Definition

A false equation is an equation that is not true for any value of the variable(s).

Description

False equations are equations that do not hold true for any value of the variable(s). For example, the equation 

x + 2 = x + 3

is false because there is no value of x that makes both sides equal. Identifying false equations is important in verifying the validity of mathematical statements.

Topic

Equations

Definition

An identity equation is true for all values of the variable(s).

Description

Identity equations are equations that hold true for all values of the variable(s). For example, the equation 

2(x + 1) = 2x + 2 

is an identity because it is true for any value of x. These equations are used to express mathematical identities and properties. In the equation above, the identity results from the use of the distributive property.

Topic

Equations

Definition

An inequation is a mathematical statement that shows the inequality between two expressions.

Description

Inequations, or inequalities, are statements that compare two expressions using inequality symbols such as >, <, ≥, and ≤. For example, 

x + 3 > 5 

indicates that 𝑥 x must be greater than 2. Inequations are used to represent constraints and conditions in mathematical models. Inequations sometimes involve the inequality symbol: ≠.

Topic

Equations

Definition

Isolating the variable involves manipulating an equation to get the variable alone on one side.

Description

Isolating the variable is a fundamental technique in algebra used to solve equations. It involves performing operations to both sides of an equation to get the variable by itself. For example, solving 

2x + 3 = 7

involves subtracting 3 and then dividing by 2 to isolate x, resulting in x = 2.

Topic

Equations

Definition

The left side of the equation refers to the expression on the left side of the equals sign.

Description

The left side of an equation is the part of the equation that appears before the equals sign. For example, in the equation 

2x + 3 = 7

the left side is 2x + 3. Understanding the left side of the equation is crucial for solving and balancing equations.

In real-world applications, recognizing the left side of an equation helps in setting up and solving problems accurately. It is essential for students to understand this concept to manipulate and solve equations effectively.

Topic

Equations

Definition

A linear equation is an equation that does not have an variables raised to a power higher than one. A linear equation can have one or more variables.

Description

Linear equations are fundamental in algebra and describe relationships are summarized below. 

Topic

Equations

Definition

A literal equation is an equation that involves two or more variables.

Description

Literal equations involve multiple variables and are used to express relationships between them. For example, the formula for the area of a rectangle, 

A = l•w

is a literal equation involving the variables l and w. Solving literal equations often involves isolating one variable in terms of the others.

Topic

Equations

Definition

A multi-step equation requires more than one step to solve.

Description

Multi-step equations involve multiple operations to isolate the variable. For example, solving 

3x + 2 = 11

requires subtracting 2 and then dividing by 3 to find x=3. These equations are common in algebra and require a systematic approach to solve.

In real-world applications, multi-step equations are used in complex problem-solving scenarios such as engineering and finance. Understanding how to solve multi-step equations helps students develop critical thinking and problem-solving skills.

Topic

Equations

Definition

The Multiplication Property of Equality states that if you multiply both sides of an equation by the same nonzero value, the equality remains true.

Description

The Multiplication Property of Equality is a fundamental principle in algebra. It states that for any real numbers a, b, and c (where 𝑐 ≠ 0), if 

a = b, then ac = bc

This property is used to solve equations by isolating variables. For example, to solve 

x/3 = 4

you multiply both sides by 3 to get x = 12.

Topic

Equations

Definition

A nonlinear equation is an equation that graphs as a curve and does not form a straight line.

Description

Nonlinear equations are equations that involve variables raised to powers other than one or involve products of variables. For example, the equation 

y = x2 

is nonlinear because it graphs as a parabola. These equations are used to model more complex relationships than linear equations.

Topic

Equations

Definition

A numerical expression is a mathematical phrase involving numbers and operation symbols, but no variables.

Description

Numerical expressions consist of numbers and operations such as addition, subtraction, multiplication, and division. For example, 

3 + 4 × 2

is a numerical expression. These expressions are evaluated to find their value.

In real-world applications, numerical expressions are used in everyday calculations such as budgeting, measuring, and data analysis. Understanding numerical expressions helps students perform arithmetic operations and develop computational skills.

Topic

Equations

Definition

A one-step equation requires only one operation to solve.

Description

One-step equations are the simplest type of equations in algebra. They involve a single operation to isolate the variable. For example, solving 

x + 3 = 7

requires subtracting 3 from both sides to find x = 4.

These equations are used in basic problem-solving scenarios and form the foundation for understanding more complex equations. Understanding one-step equations helps students develop confidence in solving algebraic problems and prepares them for advanced algebraic concepts.

Topic

Equations

Definition

A polynomial equation is an equation that involves a polynomial expression.

Description

Polynomial equations involve expressions that include terms with variables raised to whole-number exponents. For example, the equation 

x2 − 4x + 4 = 0 

is a polynomial equation. These equations can be linear, quadratic, cubic, etc., depending on the highest power of the variable.

Topic

Equations

Definition

A quadratic equation is a polynomial equation of degree 2, typically in the form ax2 + bx + c = 0.

Description

Quadratic equations are fundamental in algebra and involve variables raised to the second power. For example, the equation 

x2 − 4x + 4 = 0 

is quadratic. These equations can be solved using methods such as factoring, completing the square, and the quadratic formula.

Topic

Equations

Definition

The Reflexive Property of Equality states that any value is equal to itself.

Description

The Reflexive Property of Equality is a basic principle in mathematics. It states that for any value a, 

a = a

This property is used to justify steps in solving equations and proving mathematical statements.

In real-world applications, the reflexive property underlies the concept of identity and is fundamental in logical reasoning and proofs. Understanding this property helps students build a strong foundation in algebra and develop rigorous mathematical arguments.

Topic

Equations

Definition

The right side of the equation refers to the expression on the right side of the equals sign.

Description

The right side of an equation is the part of the equation that appears after the equals sign. For example, in the equation 

2x + 3 = 7

the right side is 7. Understanding the right side of the equation is crucial for solving and balancing equations.

Topic

Equations

Definition

The roots of an equation are the values of the variable that satisfy the equation.

Description

The roots of an equation are the solutions that make the equation true. For example, the roots of the quadratic equation 

x2 − 4x + 4 = 0

are x = 2 because substituting 2 into the equation satisfies it. Finding roots is a fundamental task in algebra.

Topic

Equations

Definition

A solution is the value(s) of the variable(s) that satisfy an equation.

Description

The concept of solution is fundamental in equations, referring to the values that make the equation true. For example, in the equation 

x + 2 = 5

the solution is x = 3 because substituting 3 in place of x results in a true statement. Solutions can exist for various types of equations, whether single-variable, multi-variable, linear, or nonlinear.

Topic

Equations

Definition

Solving an equation involves finding the value(s) of the variable(s) that make the equation true.

Description

Solving an equation is a key skill in algebra, where one determines the values of variables that satisfy the equation. For example, in the equation 

2x + 3 = 7

one can find that x = 2 by isolating the variable through algebraic manipulations. Different techniques such as substitution, factoring, or using the quadratic formula may apply depending on the complexity of the equation.

Topic

Equations

Definition

The Subtraction Property of Equality states that if you subtract the same value from both sides of an equation, the equality remains true.

Description

The Subtraction Property of Equality is a fundamental principle in algebra. It states that for any real numbers a, b, and c, if 

a = b, then a − c = b − c

This property is used to solve equations by isolating variables. For example, to solve 

x + 3 = 7

you subtract 3 from both sides to get x = 4.

Topic

Equations

Definition

The Symmetric Property of Equality states that if a = b, then b = a.

Description

The Symmetric Property of Equality is a basic principle in mathematics. It asserts that the equality relation is symmetric, meaning that if one quantity equals another, then the second quantity equals the first. For example, if 

x = y

then

y = x

This property is used to justify steps in solving equations and proving mathematical statements.

Topic

Equations

Definition

The unknown is the variable in an equation that needs to be solved for.

Description

The unknown in an equation represents the value that needs to be determined. For example, in the equation 

x + 3 = 7

x is the unknown. Identifying and solving for the unknown is a core aspect of algebra.

In real-world applications, finding the unknown is crucial for solving problems in various fields such as science, engineering, and finance. Understanding how to identify and solve for the unknown helps students develop problem-solving skills and apply mathematical concepts to real-life situations.

Topic

Equations

Definition

The Transitive Property of Equality states that if a = b and b = c, then a = c.

Description

The Transitive Property of Equality is a fundamental principle in mathematics. It states that if one quantity equals a second quantity, and the second quantity equals a third, then the first and third quantities are equal. For example, if 

x = y

and

y = z

then 

x = z

This property is used to justify steps in solving equations and proving mathematical statements.

Topic

Equations

Definition

A true equation is an equation that holds true for the given values of the variable(s).

Description

A true equation is an equation that is valid for specific values of the variable(s). For example, the equation 

2 + 3 = 5

is true because both sides are equal. Identifying true equations is important in verifying the correctness of mathematical statements.

In real-world applications, recognizing true equations helps in ensuring the accuracy of mathematical models and solutions. Understanding true equations helps students develop critical thinking and analytical skills.

Topic

Equations

Definition

A two-step equation requires two operations to solve.

Description

Two-step equations involve performing two operations to isolate the variable. For example, solving 

2x + 3 = 7

requires subtracting 3 from both sides and then dividing by 2 to find x = 2. These equations are common in algebra and require a systematic approach to solve.

In real-world applications, two-step equations are used in problem-solving scenarios such as calculating costs or determining measurements. Understanding how to solve two-step equations helps students develop critical thinking and problem-solving skills.

Topic

Equations

Definition

A variable expression is a mathematical phrase involving variables, numbers, and operation symbols.

Description

Variable expressions consist of variables, numbers, and operations such as addition, subtraction, multiplication, and division. For example, 

3x + 4

is a variable expression. These expressions are used to represent quantities and relationships in algebra.

Topic

Equations

Definition

Visual models for equations use graphical representations to illustrate the relationships between variables.

Description

Visual models for equations include graphs, charts, and diagrams that represent the relationships between variables. For example, a graph of the equation 

y = 2x + 3

shows a straight line with a slope of 2 and a y-intercept of 3. These models help in understanding and interpreting equations.

Watch the following video on Order of Operations. (The transcript is included.)

Video Transcript

A numerical expression includes numbers and operation symbols, addition, subtraction, multiplication, and division.

Because addition is commutative, adding from left to right, or right to left, gives you the same result.

The expressions 2 + 3 and 3 + 2 give the same result. But this isn't the case with all operations.

Subtraction isn't commutative.

This is part of a collection of definitions related to the topic of systems of equations. The focus of most of the terms is linear systems.

This is part of a collection of definitions related to the topic of systems of equations. The focus of most of the terms is linear systems.

This is part of a collection of definitions related to the topic of systems of equations. The focus of most of the terms is linear systems.

This is part of a collection of definitions related to the topic of systems of equations. The focus of most of the terms is linear systems.

This is part of a collection of definitions related to the topic of systems of equations. The focus of most of the terms is linear systems.

This is part of a collection of definitions related to the topic of systems of equations. The focus of most of the terms is linear systems.

In this graphing calculator activity, have your students explore how to convert linear equations in point-slope to a linear function in slope-intercept form. This Desmos template allows students to explore the effect of changes in the values of coordinates of the point and the slope of the line. A companion downloadable worksheet uses the graphing calculator template to explore the properties of these linear equations and functions.

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In this graphing calculator activity, have your students explore how to convert linear equations in standard form to a linear function in slope-intercept form. This Desmos template allows students to explore the effect of changes in the values of A, B, and C in the standard form and m and b in the slope-intercept form. A companion downloadable worksheet uses the graphing calculator template to explore the properties of these linear equations and functions. Note: The download is a PDF worksheet.

The following section includes background information on slope. This background also includes video resources and accompanying transcripts.