Evaluate the integral using integration by parts with the
indicated choice.
∫xe(9x)dx; u=x, dv=e(9x)dx.
a) (x/9)e(9x) - ∫(1/9)e(9x)dx
b) (x/9)e(9x) - (1/81)e(9x) + C
c) (x/9)e(9x) + (1/9)e(9x) + C
d) (x/81)e(9x) - (1/9)e(9x) + C