Answer
$8n^7-12n^4+13$
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{-56n^9}{-7n^2} + \dfrac{84n^6}{-7n^2}- \dfrac{91n^2}{-7n^2}
\\=8n^{9-2}- 12n^{6-2}+13n^{2-2}
\\=8n^7-12n^4+13n^0
\\=8n^7-12n^4+13(1)
\\=8n^7-12n^4+13
$
