I differentiated the e−4x and got −4ex−4x and the differentiated the bracket bit to get (2x+2) :/
Your function is product of an exponential and a polinomial function, let u=f(x) and v=g(x) so y=f(x)*g(x) Derivating y (dy/dx)you should use the product rule for these type of functions. This rule: Y' =f'(x)*g(x) + f(x)*g'(x)