Compute the following limits using l'Hopital's rule if appropriate. Use INF to denote $\infty$ and -INF to denote $-\infty$.

$\displaystyle \lim_{x\to 0} \frac{1-\cos\!\left(3x\right)}{1-\cos\!\left(7x\right)}$ =

$\displaystyle \lim_{x\to 1} \frac{8^{x}-7^{x}-1}{x^{2}-1}$ =