What function is the inverse of f (x) = x^2-25

The inverse function of f (x) = x^2 - 25 is ±√x+25

1) y=x^2 - 25

2) switch x and y

x = y^2 - 25

3) solve for y

Add 25 to both sides

y^2 = x + 25

Take the square root of both sides

y = + / - square root (x + 25)

4) replace f' (x) for y

f' (x) = + / - square root (x+25)