$\lim_{x\to0}\left(\frac{1}{3x}-\frac{1}{\sin3x}\right)$

$\left(\frac{a}{b}+11\right)\left(\frac{a}{b}+11\right)$

$2a-2b\:$

$\left(x^2-5\right)\left(x^5+5\right)$

$\frac{dy}{dx}=\frac{-\sin\left(x\right)}{y^2}$

$\:\frac{4\left(2\right)^2-5}{2\left(2\right)-3}$

$\frac{y}{xz\left(x+y\right)}+\frac{z}{xy\left(y+z\right)}+\frac{x}{yz\left(x+z\right)}$