$4-\left(-3\right)\cdot\left(-2\right)$

$\left(x-1\right)\cdot\left(2x-1\right)$

$\left(2xy\right)\left(x^2y^4\right)$

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

$\frac{x^2z}{x^2}$

$\lim_{x\to12}\left(\frac{x^2-144}{\sqrt{x+13}-5}\right)$

$\frac{4a^2b^4-64n^2}{11m^4-n}$