Answer
$5a^6+6a^2$
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.
$=\dfrac{-65a^8}{-13a^2} - \dfrac{78a^4}{-13a^2}
\\=5a^{8-2}+ 6a^{4-2}
\\=5a^6+6a^2$
