Find dy/dx if y=(x^3)(e^2x)

Use product rule. Set u=x^3 and v=e^2x. Differentiate u and v. Then dy/dx = uv'+vu' = (3x^2)*(e^(2x))+(2x^3)(e^(2x)). This problem is best explained written on a whiteboard (it's difficult to give an explanation in prose without proper formatting).