Question

Given f(x) = 2x + 5 and g(x) = 3x + 6

Answer 1

(f-g)x = 2x + 5 - (3x + 6) =  -x-1
so 
(f-g)(8) = -8-1 = -9

Answer 2

I hope this helps you



f(8)=2.8+5=21


g(8)=3.8+6=30


f-g(8)=21-30= -9