Given f(x) = 5x + 5 and g(x) = 6x + 1
then what is ( f + g )) ?

     •   f(x) = 5x + 5

     •   g(x) = 6x + 1

Now, you just sum those functions:

     (f + g)(x) = f(x) + g(x)

     (f + g)(x) = (5x + 5) + (6x + 1)

     (f + g)(x) = 5x + 6x + 5 + 1

     (f + g)(x) = 11x + 6

Therefore,

     (f + g)(– 8) = 11 · (– 8) + 6

     (f + g)(– 8) = – 88 + 6

     (f + g)(– 8) = – 82   <———   this is the answer.

I hope this helps! =)