Confirm that f and g are inverses by showing that f(x(f)) = x and g(f(x)) = x

Question

f(x) = x^2 -7, g(x) = √(x+7)

Answer 1

f(g(x)) = (√(x + 7))² - 7 = x + 7 - 7 = x

g(f(x)) = √(x² - 7 + 7) = √x² = x