Page 138 - TB_5B

The cost of text messages of company A Company A
is shown in the table. Thomas uses the
plan of company A. Let x the number of Number of Text Charge( )
text messages that Thomas used. Messages Used

How much does Thomas need to pay for the 1 20
text messages if he used four text messages?
2 40

x x 20

The cost of using one text message is 20 . x.
So, the amount that Thomas needs to pay can be represented by 20
Since he used four messages, x 4.

x 20 4 20

()

2 . Evaluate each expression for the given value of the variable.

a. 2x 5 if x 4 b. 16 5 if x 2
x
Replace x with 4 and add.
2x 5 2 4 5 13 16 5 16 53
x 2

c. 2y 1 if y 3 d. 8 3 if z 2
z

e. 4x 3 if x 5 f. z 2 if z 15
5

30. Algebraic Expressions 127