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

$\frac{\left(z^4-3z^3+27z^2-4z+4\right)}{\frac{1}{2}z-1}$

$\left(\:x\:-\:2y\:\right)\:\left(\:x\:+\:15\:y\:\right)$

$30x+3x-26x+3x-x$

$\int\frac{x^3+x+1}{x\left(x-1\right)^2}dx$

$\frac{x^3+x^2-2x+10}{x^2-8}$

$49-y^4$