Algebraic Expression and Two-Step Equations

Algebraic Expressions &
Two-Step Equations

By Brooke Devitt

Welcome & Learning Goal

Welcome! In this lesson, you will learn how to identify the parts of an algebraic expression and solve two-step equations. You will practice using interactive activities and games before taking a short quiz to show what you know. Take your time, read each question carefully, and do your best.

3x + 5

This expression means three times a number plus five.

Example

An algebraic expression is a math phrase that includes numbers, variables, and operations. Algebraic expressions do not have an equals sign.

Algebraic Expression

What Is an Algebraic Expression?

In the expression 4x + 2, the variable is x because it stands for an unknown number.

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Example

A variable is a letter that represents an unknown number. The value of the variable can change.

Variable

Identify the Variable

In the expression 7y + 9, the constant is 9.

Example

A constant is a number that does not change and does not have a variable attached to it.

Constant

Identify the Constant

In the expression 6x, the coefficient is 6 because it means 6 times x.

Example

A coefficient is the number that is multiplied by the variable.

Coefficient

Identify Coefficient

Match

Match the following

• Variable

• Constant

• Coefficient

Letter that stands for an unknown number

A number without a variable

A number multiplied by a variable

• Letter that stands for an unknown number

• A number without a variable

• A number multiplied by a variable

Drag and Drop

Which one is the variable?

5x + 8

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Placeholder

​

Drag these tiles and drop them in the correct blank above

x

5

8

5x

Drag and Drop

Which one is the coefficient?

5x + 8

​ ​ ​ ​ ​

Placeholder

​

Drag these tiles and drop them in the correct blank above

5x

5

8

x

Drag and Drop

Which one is the constant?

5x + 8

​ ​ ​ ​ ​ ​ ​

Placeholder

Drag these tiles and drop them in the correct blank above

5

8

x

5x

2x + 4 = 10

You must undo addition or subtraction first, then multiplication or division.

Example

A two-step equation is an equation that takes two steps to solve. To solve a two-step equation, you undo the operations in the opposite order.

Two-Step Equation

What Is a Two-Step Equation?

2x + 4 = 10
Subtract 4 from both sides.
2x = 6
Divide both sides by 2.
x = 3

Example

To solve a two-step equation, follow these steps carefully.

Step 1: Undo addition or subtraction.
Step 2: Undo multiplication or division.

How to Solve?

Solving a Two-Step Equation

Multiple Choice

Question 1 (Multiple Choice):
In the expression 7y + 2, what is the variable?

• 7

• 2

• y

• +

Multiple Choice

Question 2 (Multiple Choice):
What is the first step to solve the equation 3x − 5 = 10?

• Divide by 3

• Add 5

• Subtract 3

• Multiply by 5

Open Ended

Question 3 (Short Response):
Solve the equation: 4x + 8 = 20

Review Game

Game / Review Activity

Let’s review! Answer the questions below to practice identifying algebraic expressions and solving two-step equations. This activity is for practice only, so try your best and learn from your mistakes.

Summative Assessment:
Mini Quiz

Open Ended

Question 1:
Identify the variable in the expression 9k − 4.

Open Ended

Question 2:
What is the coefficient in the expression 6x + 3?

Open Ended

Question 3:
Solve the equation: 5x + 10 = 35

Completion & Support

Great job completing this lesson! If you need help or want to review the material again, you can go back through the lesson at your own pace. If you still have questions, please reach out to your teacher for support.