Mark (√) against the correct answer in the following:

Let f : N X : f(x) = 4x2 + 12x + 15. Then, f - 1(y) = ?


f(x) = 4x2 + 12x + 15


y = 4x2 + 12x + 15


y = (2x + 3)2 + 6


√(y - 6) = 2x + 3



f - 1(y) =

1