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

$\lim_{x\to infinity}\left(\frac{arctan\left(x^7\right)}{x^6}\right)$

$\left(xy+z\right)\left(z-xy\right)$

$\left(\frac{dy}{dx}\right)^2=\tan\left(x\right)$

$\frac{dy}{dx}\:+\:4y=\frac{5x^3\:+\:3}{1}\:$

$\frac{3t+3}{\left(t+1\right)^2}\le\:\:1$

$8a^3+27a^6$