Find the inverse of the function on the given domain

Question

Find the inverse of the function on the given domain f(x) = 3x^2 + 5, (−∞, 0]?

Answer 1

y = 3x^2 + 5

x = 3y^2 + 5

x - 5 = 3y^2

(x - 5) / 3 = y^2

-/[(x - 5) / 3] = y

No solutions within the restricted domain.