=(x^3+x)e^x-[(3x^2+ 1)e^x-∫6xe^xdx]

=(x^3-3x^2+x- 1+6x-6]e^x+c

=(x^3-3x^2+7x-7)e^x+c.

(3) let u=√(x+5), then x = u 2-5, dx = 2udu,

Original formula = ∫ 2UE Udu

=(2u-2)e^u+c

=[2√(x+5)-2]e^√(x+5)+c.