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

(Marvins-Underground-K-12) #1
``Q Apply``

r

``Solve each equation. Check your answer.``

38.^2 + y

``41-2 2C``

``44.^ = 5±``

``-1``

• 2
39. -2 4 = -101+3

``````42 x ~ 3 = — 4 I
3 2``````

1. 2.4 + 10m = 6.89
40. 10 = 0.3x — 9.1
43. 9.4 = —d + 5.6
46. 3= -17

``Solve each equation. Justify each step.``

1. 15 = 9 - 3p 48. 4 — 5fc = - 1 6 49. 9 +^35 = -5 50.

``````5 1. E rro r A n alysis D escribe an d correct the error in finding th e solution of the
equation at th e right.``````

1. W riting W ithout solving th e eq u a tio n - 3 x + 5 = 44, tell w h e th e r th e value of x is
positive or negative. How do you know?

2. a. Solve th e equ atio n^2 x -^1 = 7 by un d o in g subtraction first.
b. Solve th e equ atio n in p a rt (a) by un d o in g m ultiplication first. Do you get the
sam e answ er you got in p a rt (a)?
c. R easo ning W hich m eth o d from p arts (a) a n d (b) do you prefer? Explain.

``````Geometry In each triangle, the measure of LA equals the measure of LB. Find
the value of x.``````

``12 = 2``

1. Think About a Plan A Web site allows m usicians to p ost th eir songs online. Then
people using th e Web site can buy any of th e p o sted songs. Suppose each m usician
m u st pay a o ne-tim e fee of \$5 to use the Web site. Each m usician earns \$.09 every
tim e a p articular song of his or hers is dow nloaded. If a m usician ea rn ed \$365 for a
particular song, how m any tim es was the song dow nloaded? \
. • How can th e m odel at th e right help you solve th e problem?

• How does the m odel tell you w hich operations to use in the equation?

1. Open-Ended Write a real-w orld problem th a t you can m odel w ith the tw o-step
equation 8b + 6 = 38. Then solve th e problem.

2. Home Im provem ent A contractor is adding a back p orch on to a house. The porch
needs to h old 20 people a n d furniture th a t weighs 250 lb. The contractor calculates
th a t th e p orch n eeds to hold 3750 lb to m eet th a t specification. W hat value did the
contractor use for the w eight of a person?

``````-365-
0.09x``````

92 Ch ap t er 2 So l v i n g Eq u a t i o n s