Solving Equationswith

Variables on Both Sides

Module 4Lesson 4

Solving Equations with Variables on Both Sides6 2.

9 = 10x – 11 9x = 10 – 11x

What is different about these two equations?

Solving Equations with Variables on Both Sides6 2.

Practice

1. 8t – 11 = – 7t + 19 2. 4n – 8 = n + 4 + 10n – 3n

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Solving Equations with Variables on Both Sides6 2.

EXAMPLE Using the Distributive Property

21x = 3(2x + 30)

Practice

3. 2(x – 7) = 5x + 10

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Solving Equations with Variables on Both Sides6 2.

EXAMPLE Finding the Perimeter of a Triangle

Each side of the triangle has the same length. What is the perimeter of the triangle ?

5x + 9 7x + 5

Solving Equations with Variables on Both Sides6 2.

Practice

4. Find the perimeter of the rectangle.

3

4x – 3

2x + 7

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Drum lessons at the youth center costs $8 for members and $12 for non members. Membership is $24. For what number of lessons is the cost the same for a member and a nonmember?

Solving Equations with Variables on Both Sides6 2.

EXAMPLE

Member fee

Price for members+

Cost for member

Price for nonmembers

Cost for nonmember

=

Collecting Like Terms

• Number of lessons • Number of

lessons

24 + 8l = 12l Write algebraic model.

24 + 8l = 12l

24 = 4n

n = 8

Subtract 8l from each side.

Combine like terms.

Divide each side by 4 then simplify.

– 8l – 8l

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