# Algebra 1 Common Core Student Edition, Grade 8-9

(Marvins-Underground-K-12) #1

How can a model
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``