[m]\large = \frac{3ax^3+2bx^2 - ax^3 - bx^2 - c}{(a+b)x^2} = \frac{2ax^3+bx^2 - c}{(a+b)x^2}[/m]
16) [m]\large \bigg ( \left ( \frac{mu + n}{p} \right )^3 \bigg )' = \bigg ( \frac{(mu + n)^3}{p^3} \bigg )' = \frac{3(mu + n)^2 \cdot (mu + n)'}{p^3} = \frac{3m(mu + n)^2}{p^3}[/m]