Ok first we can split it in two : \(e^{x^2+2x}\) and \(3x\).
The derivative of \(3x\) is 3.
For the first part, we use the chain rule : \([f(g(x))]'=g'(x)f'(g(x))\) hence \((e^{x^2+2x})'=(x^2+2x)'e^{x^2+2x}\) (since the derivative of the exponential is itself) hence \(g'(x)=(2x+2)e^{x^2+2x}+3\)
