Step-by-step explanation:
f(1) = 7
for n = 1
f(2) = f(2 - 1) + 2 = f(1) + 2 = 7 + 2 = 9
f(3) = f(3 - 1) + 2 = f(2) + 2 = 9 + 2 = 11
f(4) = f(4 - 1) + 2 = f(3) + 2 = 11 + 2 = 13
