Algebra 1 Common Core Student Edition, Grade 8-9

Writing Real-World Inequalities

5, can th e sp eed b e all real n u m b ers less

Plon^

How do you know

which inequality

sym bol to use?

The phrase "starting at

$19.99" implies th a t the

cost o f a tra il ride starts

at $19.99 and goes up.

$o the cost is greater

than or equal to 19.99. Let s = a legal speed in m iles p er hour.

The sign indicates th a t s < 8.

What inequality describes the situation?Besure to define a variable.

Let c = th e cost of a trail ride in dollars.

The sign indicates th a t c > 19.99.

Got It? 5. Reasoning In p a rt (B) of Problem

th a n or equal to 8? E x p l a i n.

Co n cep t Su m m a r y Representing Inequalities

Words Symbols Gr ap h

x is less th a n 3. x < (^3) - 2-1 0 1 2 3 4 5 6
x is greater th a n - 2 .x> -2 - 4 - 3 - 2 - 1 0 1 2 3 4
x is less th a n or equal to 0. x —^0 -4 -3 -2 -1 0 1 2 3 4
x is greater th a n or eq u al to 1. X ^ 1

• 4 - 3 - 2 - 1 0 1 2 3 4
  V ........J

& Lesso n Ch eck

Do y o u k n o w H OW?

1. W hat algebraic inequality represents all real
   numbers y th a t are greater th a n or equal to 12?


2. Is the n u m b e r a solution of 6 x - 3 > 10?
   a. - 1 b. 0 c. 3 d. 4


3. W hat is th e graph of 2 > p?


4. W hat inequality represents th e graph?
   « I I "
   -5 -4

H h -I h

MATHEMATICAL

Do y o u UN DERSTAND? ^PRACTICES

5. Vocabulary How do you decide w h e th e r a n u m b e r is
   a solution of an inequality?


6. Co m p a r e a n d Co n t r a st What are some situations
   you could m odel w ith x^O? How do they differ from
   situations you could m odel w ith x > 0?


7. Open- Ended W hat is a real-w orld situation th a t you
   can re p resen t w ith the following graph?
   H h
   -2 -1 1 5 10 15 20 25 30 35

c

Po w erAlg eb ra.com £ Lesson 3-1 In eq u al i t i es an d Th ei r Gr ap h s^167