$\int e^x \cdot x^5 \, dx$ is
$e^x\left[x^5 + 5x^4 + 20x^3 + 60x^2 + 120x + 120\right] + C$
$e^x\left[x^5 - 5x^4 - 20x^3 - 60x^2 - 120x + 120\right] + C$
$e^x\left[x^5 - 5x^4 + 20x^3 - 60x^2 + 120x - 120\right] + C$
$e^x\left[x^5 + 5x^4 + 20x^3 - 60x^2 + 120x - 120\right] + C$
