integral(x^2)(e^-x)dx

the answer given was (-x^2)(2e^-x - e^-x)+c

during one of the steps i have (-x^2) + 2[-x(e^-x)+integral(e^-x)dx]

so when you multiply or distribute that second part by the 2 shouldnt you end up with (-x^2)(2e^-x -e^-x)+c ?2