$\frac{6x^2-xy-2x^2}{y+2x}$

$6x^2+7x-20$

$\lim_{x\to\infty}\left(\frac{e^{-x}}{ln\left(1+7e^{-x}\right)}\right)$

$\lim_{x\to0}\left(\frac{2\sqrt{x^2+4}}{x}\right)$

$\int\:\frac{3x\cos\left(x^2\right)}{\left(5+\sin\left(x^2\right)\right)^2}dx$

$\left(6x^4+5\right)\left(6x^4-5\right)$

$5^{9-\left(0\right)^2}$