Evaluate $\frac{7!+8!}{6!+7!}$. Express your answer as a common fraction.
We notice that 6! is a common factor of the numerator and denominator and then simplify: \begin{align*}
\frac{7!+8!}{6!+7!} &= \frac{7\cdot6!+8\cdot7\cdot6!}{6!+7\cdot6!} \\
&=\frac{6!(7+8\cdot7)}{6!(1+7)} \\
&=\frac{7+56}{1+7}\\
&=\boxed{\frac{63}{8}}\\
\end{align*}