Two-Step Equations

Standards CC.8.EE.7 Solve linear equations in one

variable.

Let’s look at pg. 171 Let’s walk through the activity.

Now let’s work through number 2.

Definitions Two-step equation- an equation that

contains two operations. To solve it, you have to undo each operation in reverse order.

Coefficient- a numerical factor of a term that contains a variable.

Reflexive Property of Equality- for any numbers a and b, if a = b, then b = a. So you can switch them.

Questions: 3x = 12 How would you solve this equation? Suppose you add 2 to each side of the

equation. What is the resulting equation? Do the equations 3x = 12 and 3x + 2 =

14 have the same solution? What would you have to do to the

equation 3x + 2 = 14 to make it look like the equivalent equation 3x = 12?

Questions In an equation such as 3p + $2.50 = $7,

which operation should be undone first? Second?

Let’s practice 2x + 3 = 7

Let’s practice 25 = ¼ n - 3

Let’s practice 6 – 3x = 21

Let’s practice

3x + 2 = 20

Let’s practice 5 + 2n = -1

Let’s practice -1 = 1/2a + 9

Let’s practice 10 – 2/3p = 52

Let’s practice Simon has $150 for a class trip that

costs $320. He needs to save money for the next 10 weeks in order to pay for the trip. Solve the equation 10d + 150 = 320 to find the amount of money per week Simon must save.

Let’s practice Melissa wants to put trim molding

around a rectangular table. The length of the table is 45 inches and she has 150 inches of trim. Solve the equation 150 = 2w + 90 to find the width of the table.