$7x+3x+2y+4$

$x^6+8x^2+\frac{16}{x^2}$

$\lim_{x\to\infty}\left(\frac{\left(x+a\right)}{\left(x-a\right)}\right)^x$

$\int_4^{-4}\pi\left(1-\frac{x^2}{16}\right)^2dx$

$\frac{x^2+3x}{x+1}$

$\frac{dy}{dx}\cdot x+y=4x$

$y''+2y'+10y=0,\:y\left(0\right)=-2\:and\:y'\left(0\right)=0$