$-\frac{2tanx}{1-sec^2x}$

$\lim_{x\to\infty}\frac{\left(4x^2+3\right)}{5x^3+7}$

$3xa^2\:-\:4a^2x\:+\:10xa^2$

$\frac{4}{3}+2\le3$

$\lim_{h\to0}\left(\frac{sin\:2x\left(\:cos\:\left(2h\right)-1\right)}{h}\right)$

$3\left(x-1\right)-2\left(x-1\right)-6\le2x$

$\left(x-1\right)\left(x^2-4x+4\right)$