G8

Copyright © Copyright © Swun MathSwun Math (^) Grade 8 Unit 4 Lesson 2 P TE

Input/Model

(Teacher Presents)

Directions: Identify an inverse operation to use. Solve and check your solution.

1. x + 3 = 10

Solution:

• Identify operation in the equation: ADDITION


• Identify inverse operation needed to solve: SUBTRACTION
  푥푥+ 3 = 10
  − 3 − 3
  푥푥= 7

Answer: 푥푥= 7

Check. 7 + 3 = 10

10 = 10 ✓

2. ─3m = 15

Solution:

• Apply the multiplicative inverse of –3: divide by –3 or multiply by −^13.
  − 3 푚푚
  − 3 =

15

− 3

푚푚= − 5

Answer: m = − 5

Check: −3 • −5 = 15

15 = 15 ✓

푥푥

3 =−^9

Solution:

• Apply the multiplicative inverse of^13 : multiply by 3.

3 •

푥푥

3

=−9 • 3 → 1 3 •

푥푥

(^31)

=−9 • 3

푥푥= −9 • 3

Answer: 푥푥= − 27

Check: −27 3 =− 9

− 9 = − 9 ✓