$\lim_{x\to1,4}\left(\frac{64x^2-y^3}{4xy-y^2}\right)$

$\frac{\sec\left(x\right)+\tan\left(x\right)}{1}=\frac{\cos\left(x\right)}{1-\sin\left(x\right)}$

$\lim_{x\to0}\left(\frac{4^x+2^x}{6^x}\right)$

$\left(b-d\right)^3$

$\frac{x}{\left(16+x^4\right)}$

$16h^4-625$

$a-22=-31$