Answer
$-8ab-10a^2b^3$
Work Step by Step
Recall the following rule: $\frac{a^{m}}{a^{n}}=a^{m-n}$
In order to solve this problem, use the rule above and cancel out common factors that are in both the numerator and the denominator of the fraction.
$=\dfrac{48a^2b^2}{-6ab} + \dfrac{60a^3b^4}{-6ab}
\\=-8a^{2-1}b^{2-1}- 10a^{3-1}b^{4-1}
\\=-8ab-10a^2b^3$