How can a model

help you w rite the

equation?

The model shows th a t

the cost o f the niece's

items plus the cost o f the

nephew's items is $67.

f..............^67 ..................-I

1 s + 4 [ 2s 1

`^ Got II? 1. W hat is th e solution of each equation? C heck ea ch answer.`

a. l l m - 8 - 6 m = 22 b. -2y + 5 + 5y = 14

`Pr o b l em 2 So l v i n g a M u l t i - St ep Eq u at i o n`

Concert Merchandise Martha takes her niece and nephew to a concert.

She buys T-shirts and bumper stickers for them. The bumper stickers

cost $1 each. Martha's niece wants 1 shirt and 4 bumper stickers, and her

nephew wants 2 shirts but no bumper stickers. If Martha's total is $67,

what is the cost of one shirt?

- Bumper stickers cost $1
- Niece's items: 1 shirt, 4 bumper

stickers - Nephew's items: 2 shirts
- Total spent: $67

`The cost o f one shirt W rite and solve an equation`

that models the situation.

`cost of niece's cost of`

Relate item s (1 shirt a n d plus n e p h e w ’s item s is

4 stickers) (2 shirts)

`Define Let s = th e cost of one shirt.`

`Write (s + 4) + 2s`

`(s + 4) + 2s = 67`

s + 2s + 4 = 67

3s + 4 = 67

3s+ 4 - 4 = 67- 4

3s = 6 3

3s _ 63

3 3

s= 21

`O ne shirt costs $21.`

`total M artha`

spent

`67`

`Commutative Property of Addition`

Combine like terms.

$ u b tra c t 4 fro m each side.

Simplify.

D ivide each side by 3.

Simplify.

`si Got It? 2. Noah a n d Kate are sh opping for n ew guitar strings in a m usic store.`

N oah buys 2 packs of strings. Kate buys 2 packs of strings an d a

m usic book. The b ook costs $16. Their total cost is $72. How much

is one pack of strings?

c

`PowerAlgebra.com Lesso n 2-3 So l v i n g M u l t i - St e p Eq u a t i o n s^95`