a) f(2) = [ 2 + 3 ] /2 = 5/2
b) for f(x), write y
y = [ x + 3 ] / 2 multiply both sides by 2
2y = x + 3 subtract 3 from both sides
2y - 3 = x "swap" x and y
2x - 3 = y = f-1(x)
c) f-1 (12) = 2(12) - 3 = 24 - 3 = 21