$5\tan x=\tan x$

$5x^2+12x+15$

$\frac{d}{dx}\left(x^3+y^3=3x^2y-3xy^2\right)$

$z^4\left(2z-8\right)^3$

$-\frac{10x^2}{x^3}$

$\lim_{x\to0}\left(\frac{y\left(cos\left(m\right)cos\left(x\right)-sin\left(m\right)sin\left(x\right)\right)-ycos\left(m\right)}{x}\right)$

$3.2-7+5\:\left(12-20\right)$