$\frac{31z^{14}}{20z^7}$

$\int\frac{\left(x-1\right)}{\left(x^2+9\right)}dx$

$\left(x-2\right)^2\left(x-3\right)^2$

$\lim_{x\to0}\left(\frac{e^x-1-ln\left(1+x\right)}{x^2}\right)$

$\int\frac{7x-9}{\left(x^2+4\right)\left(x-1\right)}dx$

$\left(x+3y\right)\left(x-2y\right)\left(x+y\right)$

$\left(x+12\right)\:\left(x-4\right)$