[tex]\int{(x+1)e^x} dx[/tex]
Integrate by parts: [tex]\int{fg'} = fg - \int{f'g}[/tex], where [tex]f = x+1[/tex], [tex]g' = e^x[/tex], [tex]f' = 1[/tex] and [tex]g = e^x[/tex]
[tex]\int{(x + 1)e^x} dx = (x+1)e^x - \int{e^x} dx\\= (x + 1)e^x - e^x + C = xe^x + C[/tex]