pre calculus hw

Question

If g(x) = x^2 + 10x with x ≥ −5, find g^−1(75).

Answer 1

y = x² + 10x; domain: x ≥ -5, range: y ≥ - 25;

75 = x² + 10x; x = -5 ± 10; x = 5 (x = - 15 not in range of inverse function). So, g^-1(75) = 5