There is no equation because there’s no equals sign, so it’s just an expression.
Let’s use different brackets to clarify:
{[(9-x^2)^1/2]+x^2(9-x^2)^1/2}/9-x^2 =
{(9-x^2)^1/2+x^2(9-x^2)^1/2}/9-x^2
(9-x²)^½ is a common factor: let’s write it as √(9-x²):
((1+x²)√(9-x²))/9 — x²