Question

Given that f(x) = 2x - 4 and g(x) = 2x + 8, determine gf(3)

Answer 1

$\text{Given that,} ~f(x) = 2x-4~~ \text{and}~~ g(x) = 2x+8\\\\ g(f(3))\\\\=g(2\cdot 3 -4)\\\\=g(2)\\\\=2(2)+8\\\\=4+8\\\\=12$