$\frac{x^2\:+\:x\:+\:1}{x\:+\:2}$

$2m-4n+8n-5m$

$\lim_{x\to\infty}\:\left(5+\frac{1}{x}\right)^{\frac{3}{x}}$

$\frac{dy}{dx}\left(x+\sqrt[2]{xy}+y=1\right)$

$\frac{15^2}{15^{-2}}$

$\left[\left(x+5\right)+y\right]\left[\left(x+5\right)-y\right]$

$4m^2n^3\left(-2mn-3m^2n^2-5m^3n^2\right)$