$4xy+2xz-6+5xz-8xy+13$

$\frac{dy}{dx}=\left(\frac{\left(7-x\right)}{y+11}\right)$

$\frac{dy}{dx}\left(64xy\right)^{\frac{1}{3}}$

$\lim_{x\to\infty}\left(\frac{1-sin\left(x\right)}{1+cos\left(2x\right)}\right)$

$\left(500+\right)+\left(750+\right)$

$6x-30+2x$

$-5\:\left(a\:-\:11\right)\:=\:-15$