Differentiate: 3/(3-x^2)^2

I need help finding the derivative of this so any help would be great...thanks a lot :))

f(x) = 3/(3-x^2)^2 = 3(3-x^2)^(-2)

f'(x) = 3*(-2)(3-x^2)^(-3)(-2x) = 12x(3-x^2)^(-3) = 12x/(3-x²)³

If u and v are functions of x then
y = u/v
dy/dx = [v(du/dx) - u(dv/dx)]/v^2

dy/dx = [{(3 - x^2)^2}*(0) - 3*2*(3 - x^2)*(-2x)]/(3 - x^2)^4
dy/dx = [12x(3 - x^2)/(3 - x^2)^4
dy/dx = 12x/(3 - x^2)^3