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#