Question

If f(x) = 5x + 40, what is f(x) when x = –5?

a.–9
b.–8
c.7
d.15

Answer 1

Just plug the number

_5(5)+40=-25+40

=15

Answer 2

f(x)=15 d.

Explanation:

To begin solving the equation you need to substitute -5 in for x.

The equation would then read f(x)=5(-5)+40

Then you need to simplify 5 times -5 is -25

the equation would be f(x)=-25+40

Then you would simplify and you will get f(x)=15