If f(x) = 8-10x and g(x)=5x+4, what is the value of (fg)(-2)?

1 Answer
Apr 19, 2017

-168

Explanation:

Just to be clear, I'm interpreting

(fg)(-2)

as

(fg)(-2)= f(-2)\times g(-2).

We can calculate each of these smaller bits using the definitions of the functions you gave in the question with x=-2.

f(-2)=8-10(-2)=8+20=28
g(-2)=5(-2)+4=-10+4=-6

Then, the question becomes:
(fg)(-2) = 28\times -6 =-168