$\lim_{x\to-4}\left(\frac{2x^2-32}{x+4}\right)$

$\frac{dy}{dx}=\frac{\left(x-2\right)\left(y+1\right)}{xy-2y+2x-4}$

$x^2\frac{dy}{dx}+xy=x^3\cos\left(x\right)$

$v=\frac{1}{3}bh$

$\left(1+e^x\right)y'-cot^2y=0$

$\int\frac{21}{\sqrt{x^2+9}}dx$

$-17\:-\:\left(-1\right)\:+\:1$