$\lim_{x\to4}\left(\frac{x+4}{\left(x-4\right)^4}\right)$

$\frac{dy}{dx}+\frac{2y}{x}=e^x$

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

$\log xyz-\log x+\log y$

$\:\left(0.3\right)\left(-.02\right)\left(0.5\right)$

$\lim_{x\to\infty}\left(\sqrt{\left(2x^2+1\right)}-2x\right)$

$\frac{\left(1-x\right)}{\left(x-1\right)}$