How can a model
help you w rite the
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.
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
- 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
O ne shirt costs $21.
total M artha
Commutative Property of Addition
Combine like terms.
$ u b tra c t 4 fro m each side.
D ivide each side by 3.
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?
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