Consider the cubic y = f(x) = x^2(ax-b) where a > 0 and b < 0

Sketch the graph of y = f(x)

How would I do this?

Find the coordinates of the local maximum, local minimum and inflection points in terms of a and b.

I know that the first and second derivative needs to be calculated, then they are found when f'(x) and f''(x) equal 0

Any help given will be greatly appreciated

Thanks in advance