Can anyone help me out... I know that on problem like $\displaystyle 5(5+5x^2)^5 y= 5u^5 , u=5+5x^2 $ you find the derivtive of those using simple differentiation, and them combine and so on.

However, I'm not sure how to do this: find the equation of a tangent line to the graph of f using x=-2 on an equation of $\displaystyle f(x)=6x^2(3-6x^2)^5 $

I thought that was the derivative, how can this be accomplished. Simply plugging in -2 did not work. .