Answer:
6 and 7
Step-by-step explanation:
(a)
To evaluate f(3) substitute x = 3 into f(x), that is
f(3) = 2(3) = 6
(b)
To evaluate gf(3) substitute f(3) = 6 into g(x), that is
g(6) = 6 + 1 = 7
