How would you find the derivative of (3/(x^3-4)) by using the chain rule?

Let u(v) = 3/v and v(x) = x^3 -4

The original function is u[v(x)]

du[v(x)]/dx = du/dv * dv/dx
= -3/v^2 * (3x^2)
= -x^2/(x^3 -4)^2