1. Solving 2-Step Variable Equations

2. What??? Relax!! You’ve already learned 1-step!
You’ll use what you already know to solve 2-step equations.

3. STEP 1
The first step – figure out the order that you would DO to solve if you knew the value of the variable.

4. STEP 2
The second step – is to complete UNDO those steps by working in reverse order using inverse operations! + - ÷ •

5. Whatever we do on one side, we have to do on the other.
Let’s try a problem.
8x + 5 = 61
So to UNDO:
-Subtract 5 then…
-Divide by 8.
- 5
- 5
We would first DO:
-Multiply by 8 then…
- Add 5 so… = 56 8x
Whatever we do on one side, we have to do on the other.

6. Now, Step 2.
8x = 56
Whatever we do on one side, we have to do on the other.
This problem has multiplication, so we need to divide now. 8 8 x 7 =

7. Whatever we do on one side, we have to do on the other.
Let’s try a problem.
-5x + 3 = 38
- 3
- 3
UNDO in reverse…
-Subtract 3
-Divide by -5
DO originally…
Multiply by -5
Then, add 3 = 35
-5x
Whatever we do on one side, we have to do on the other.

8. Now, Step 2.
-5x = 35
Whatever we do on one side, we have to do on the other.
This problem has multiplication, so we need to divide now. -5 -5 x -7 =

9. Let’s try another problem.
+ 9
+ 9
DO originally…
Divide by -4
Subtract 9
UNDO in Reverse…
- Add 9 = 40
Multiply by -4
Whatever we do on one side, we have to do on the other.

10. Now, Step 2.
This problem has division, so we need to multiply now. a =
-160
Whatever we do on one side, we have to do on the other.

11. Let’s try another problem.
DO originally…
-Subtract 8
-Divide by 3
UNDO in
reverse…
Multiply
by 3
- Add 8
a - 8 = 12
Whatever we do on one side, we have to do on the other.

12. Now, Step 2.
a - 8 = 12
+ 8
+ 8 a 20 =
Whatever we do on one side, we have to do on the other.

13. Now you try some problems.
Copy these problems onto a piece of paper.
Break each problem into 2 parts to solve.
Show all your work!
7f + 5 = 40

14. Now you try some problems.
Copy these problems onto a piece of paper.
Break each problem into 2 parts to solve.
Show all your work!
7f + 5 = 40
t=5
t = 186
m = 100
y = -80