Đáp án:
$\begin{array}{l}
1)a)\\
\left( { - 5{a^5}{b^3} + 3{a^6}{b^2}} \right):4{a^4}{b^2}\\
= - \dfrac{5}{4}ab + \dfrac{3}{4}{a^2}\\
b)\left( {\dfrac{1}{3}{a^3}b + \dfrac{1}{3}{a^2}{b^2} - \dfrac{1}{4}a{b^5}} \right):5ab\\
= \dfrac{1}{{15}}{a^2} + \dfrac{1}{{15}}ab - \dfrac{1}{{20}}{b^4}\\
2)\\
\left( {3{x^4} + \dfrac{1}{3}{x^2}} \right):x - {x^3}:3{x^2} + {\left( {3x} \right)^3}\\
= 3{x^3} + \dfrac{1}{3}x - \dfrac{1}{3}x + 27{x^3}\\
= 30{x^3}
\end{array}$