Is the following true or false? d/dx[x^3e^x]=x^2e^x (3x+2)

It's false. It's a product so...
Derivative of the first TIMES the second PLUS derivative of second TIMES the first.

Derivative of the first (x^3) = 3x^2
Times the second = 3x^2 * e^x

Derivative of the second = e^x (remains unchanged)
Times the first = e^x * x^3
So the answer would be (3x^2)(e^x) + (e^x)(x^3)
which can be factorised to form x^2·e^x(3 + x)