$\left(\left(x+5\right)\left(x+8\right)+2x\right)$

$-12\cdot3+18$

$\left(-5\right)\left(-2\right)\left(-1\right)\left(-1\right)\left(-2\right)$

$\lim_{x\to12}\left(\frac{\sqrt{x}-\sqrt{12}}{x^2-144}\right)$

$2x\:cos\:360\:-3x\:tg\:135\:+\:cotg\:225$

$\frac{dy}{dx}=x^2\left(x-xy\right)$

$2\frac{dy}{dx}=y^2\cos\left(x\right)$