$15x^4\:+\:20x^3-\:35x^2\:+\:45x$

$\cos2x+\sqrt{2}\sin x=1$

$\left(6m+3\right)\left(m+n\right)$

$\left(cos\:\left(x\right)-10\right)^2$

$\lim_{x\to6}\left(\frac{5\left(x-6\right)\sqrt{x+10}}{4-\sqrt{x+10}}\right)$

$\frac{\infty}{5}$

$\lim_{x\to\infty}\left(\frac{\sqrt{x^4+2x}}{x^3+1}\right)$