Algebra 1 Common Core Student Edition, Grade 8-9

Pl an
How do you know
which inequality
sym bol to use?
Look a t th e a rro w to see
w h e th e r th e s o lu tio n is
for quantities greater
th a n o r less th a n th e
endpoint. Look at the
e n d p o in t to see w h e th e r
"e q u a l t o " is included in
the solution.

Problem 3 Graphing an Inequality

What is the graph of 2 5: a?

If 2 is g re a te r th a n o r equal to

a, th e n a m u st be less th a n o r

equal to 2 ,

Write

a< 2

a < 2 m eans all real

num bers a th a t are less

th a n o r equal to 2. Since 2

is a s o lu tio n , d ra w a closed

dot at 2.

H 1 ----- 1 ----- 1 -

-4 -3 -2 -1 0 1 2 3 4

The num bers less th a n 2 are

to the left o f 2 on the number

line. Shade to th e le ft o f 2.

<+■

-4 -3 -2 -1 0 1 2 3 4

0 G o t It? 3. W hat is th e graph of each inequality?

a. x > -4 b. c < 0 c. 3 < n

Writing an Inequality From a Graph

What inequality represents the graph?

H h

1

"I"" I"'

1 2

0 >#-+■ H 1 ...... 1 ...... 1

-2 -1 1

The closed dot means

tha t -1 is a s o lu tio n.

The open d ot means

t h a t 4 is not a s o lu tio n.

The n u m b e r lin e is sh a d e d to

the rig ht o f - 1 , s o a l l n u m b e r s

greater than -1 are solutions.

The num ber line is shaded to

the le ft o f 4, so all numbers

less th a n 4 are s o lu tio n s.

The inequality x > - 1 represents the graph. The inequality x < 4 represents th e graph.

* G o t It? 4. W hat inequality represents each graph?

a. 1 —©—h

-5 -4 -3 -2

H h

b. I 1 h

-3 -2 -1

H h 4-*~

166 Chapter 3 Solving Inequalities