Find the inverse of the following function.

f (x) = 3squareroot x + 12

F (x) = 3 · √x + 12

Let f (x) = y

y = 3 · √x + 12

y - 12 = 3 · √x ... (Subtract 12 from both sides)

(y - 12) / 3 = √x ... (Divide both sides by 3)

(y/3) - (12/3) = √x

(y/3) - 4 = √x

[ (y/3) - 4]² = x ... (Square both sides)

Therefore, f⁻¹ (y) = [ (y/3) - 4]²

f⁻¹ (x) = [ (x/3) - 4]²