$12x-36x+2x$

$\left(3x+4y+5z\right)+\left(7y+3z-8x\right)$

$\lim_{x\to\infty}\left(100\cdot\frac{x^2+10x+100}{x^2+20x+100}\right)$

$-5+105+\left(\sqrt{36.\:\left(-1\right)}\right)^3$

$\frac{\cot^2\left(x\right)-1}{\cot^2\left(x\right)+1}=1-2\sin^2\left(x\right)$

$ln\left[\frac{x^4\sqrt{x^2+4}}{\left(x+4\right)^3}\right]$