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

     •   f(x) = 2x + 5

     •   g(x) = 3x + 6

To evaluate  f(g(x)),  replace  x  with  g(x)  in the equation of  f:

     f(g(x)) = 2 · g(x) + 5

     f(g(x)) = 2 · (3x + 6) + 5

     f(g(x)) = 2 · 3x + 2 · 6 + 5

     f(g(x)) = 6x + 12 + 5

     f(g(x)) = 6x + 17

Therefore,

     f(g(8)) = 6 · 8 + 17

     f(g(8)) = 48 + 17

     f(g(8)) = 65   <————    this is the answer.

I hope this helps! =)