How do I simplify this expression: y=((x^(2)-9)^(2)(-2x)-(-x^(2)-9)(s(x^(2)-9)(2x)))/(x^(2)-9)^(4))?

Question

I'm trying to simplify this equation to then figure out my second derivative.

Answer 1

If you look really carefully, in the numerator you can factor out a (x^2 - 9)^2 - there's two in the first term of the numerator and there is a (x^2 - 9) listed twice in the second term. Factoring those and cancelling some in the denominator leaves you with:

(-2x -2xs) / (x^2 - 9)^2