G8

Copyright © Swun Math Grade 8 Unit 2 Lesson 7 P TE

Input/Model

(Teacher Presents)

Directions: Simplify the expression. Write the solution using a positive exponent.

1. 6 −^8 ⋅ 68

Solution:

1 st Strategy

• 6 −8+8 (keep in mind the rules for adding exponents)


• 60 = 1

2 nd Strategy

● Change each number so they have positive exponents.

● 618 ⋅ 68

● 6

8

68

● 60 = 1

3푥푥^5 ⋅ 푥푥−^2

푥푥^4

Solution:

1 st Strategy

• Since they have the same base, add exponents in the numerator. Then subtract with the exponents that
  have the same base in the denominator.


• 3푥푥

3

푥푥^4 = 3⋅푥푥

3−4 (Students might want to write 4 – 3)

• 3 ⋅푥푥−1=^3 푥푥

2 nd Strategy

• Use expanded form and cancel the common factors.


• 3⋅푥푥⋅푥푥⋅푥푥⋅푥푥⋅푥푥⋅푥푥

−1⋅푥푥−1

푥푥⋅푥푥⋅푥푥⋅푥푥 change the two negative exponents so they are positive.^

• 31 ∙푥푥푥푥∙푥푥푥푥∙푥푥푥푥∙푥푥푥푥∙푥푥푥푥∙^1 푥푥→^31 ∙^1 푥푥

• 31 ⋅^1 푥푥=^3 푥푥