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

(Marvins-Underground-K-12) #1
``````Acing the Test
Doing well on tests, whether they are chapter
tests o r state assessm ents, d e p e n d s o n a d e e p
understanding o f math concepts, fluency with
calculations and com putations, and strong
problem -solving abilities.``````

``````All of these opportunities for practice
th ro u g h o u t the y e a r inclu d in g
the assessm ents to m easure y o u r
proficiency with the
Common Core
State Standards.
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«.(2.2),(U) 8. (-1,2), (0,5) 9. (-3, -2), (-3.2)?. (4,2),(0,2)``````

``````.lope- a-I-ft- 2
5-2 Direct Variation``````

``````TIPS FOR SUCCESS
Some questions on standardized
tests ask you to use a graph.
the right. Then follow the tips to
TIP 1
Identifying the y-intercept may
help eliminate some possibilities.``````

``````What is an equation of the line shown
below?``````

``````C7D y * f * - 1
>y* 3*``````

``CO y = 3* - 1``

``````TIP 2
Find the slope by using the point that represents the
y-intercept and another point on the line.``````

``````Think I f Through
You can see from die graph that
the y-intercept is - 1. So you
can eliminate choices B and D.
To get from (0, - 1 ) to (1,2),
move3 units up and 1 unit to
die right. The slope is f = 3. So
an equation is y ** 3* - 1. The

``<0 Vocabulary Buiidor``

k Review
tio n represents a d irec t v ariatio n If it has the form
x, where k * 0. The coefficient k is the co n s ta n t
iation.

ipie
tse y varies directly with , and y = 15 w h e n = 5.
a direct variation equation th at relates and y. W hat
value ofy w h e n
= 9?
= k{ 5) Substitute 5 for x and 15 for y.
» k Divide each side by 5 to solve for k.
= 3 Write an equation. Substitute 3 for k in y = kx.
(uationy ® 3
relate s a n d y .W h e n = 9 ,y = 3(9),

``````Exercises
Suppose y varies direcdy with *. Write a direct variation
equation th at relates * and y. Then find th e value of y when
* = 7.``````

1. y 8 w hen

2. y 3 when =

1. y 15 when * 6.

1. y * - 4 w hen » 4.
For th e da ta in each table, tell w hether y varies directly
w ith
. If it does, write a n eq uation for the direct variation.

3. ISIS -1 -6 C M-3 7.
2 3 - 1 2.
512 2-
9 24 5 -1 2 5

``````At the end of the chapter, you'll find a Quick R©vi©W
of the concepts in the chapter and a few examples and
exercises so you can check y o u r skill a t solving problem s
related to the concepts.``````

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``````In th e C u m u la tiv e S ta n d a rd s R e v ie w
at the end of the chapter, you'll
also find Tip s f o r Su ccess,
rem inders to help w ith problem
solving. W e include problem s of all
different formats and types so you
can feel com fortable w ith any test
item o n y o u r state assessm ent.``````

``Using Your Book f or Success xvii``