## Elementary Algebra

$-7n^2+9$
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. $=\dfrac{-42n^6}{6n^4} + \dfrac{54n^4}{6n^4} \\=-7n^{6-4} + 9n^{4-4} \\=-7n^2+9n^0 \\=-7n^2+9(1) \\=-7n^2+9$