a) $\boxed{6x + 13}$
b) $\boxed{-12x^3 - 9x^2 + 6x}$
c) $\boxed{x^4 - x^3 + x^2 - x - 37}$
d) $\boxed{2x^2 + \frac{1}{2}}$
e) $8x^5 - 18x^4 + \frac{48}{5}x^3 - 15x^2$