$\frac{36xy}{-6}$

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

$\frac{dy}{dx}\left(\frac{y}{3}-\frac{x}{y}=6\right)$

$2x^2-13x+15$

$\lim_{x\to\infty}\left(\frac{-ln\left(x\right)-1}{x}\right)$

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

$\frac{-52abc}{-4ab}$