$2x^2-3y^2+5xy-4x^2+7xy-6y^2$

$4b^{-3}c^33a^{-2}b^{-3}c^{-3}$

$\sqrt{a}-\frac{1}{2}\sqrt{a}+3\sqrt{a}$

$\lim_{x\to\infty}\left(\frac{\arctan\left(x\right)}{x}\right)$

$\left(x+8\right)\left(x+7\right)$

$\frac{d}{dx}\left(sin\left(9x\right)^{7x}\right)$

$\frac{d}{dy}2x^2-3y-4$