Exercise 7 Page 125

To evaluate a function for a certain value of x means that we substitute the given value for every instance of x. Let's do this for the given function when x=-2.

p(x)=-3+4x

Substitute

x= -2

p( -2)=-3+4( -2)

MultPosNeg

a(- b)=- a * b

p(-2)=-3+(-4 * 2)

Multiply

Multiply

p(-2)=-3+(-8)

AddNeg

a+(- b)=a-b

p(-2)=-3-8

SubTerm

Subtract term

p(-2)=-11

When x=-2, the function's value is -11. We will evaluate this function for x=0 and x=5 in the same way using the table below.

x	-3+4x	p(x)
-2	-3+4( -2)	-11
0	-3+4( 0)	-3
5	-3+4( 5)	17