$\frac{x^{15}-y^{15}}{x-y}$

$\left(3x^2\right)^2-\:2\left(3x\right)\left(9\right)+\left(9^2\right)$

$-11\:-\:5\:\left(-2\right)\:$

$\frac{\tan\theta}{\cot\theta}+1=\sec^{2}\theta$

$-sin\left(y\right)\frac{dy}{dx}=1$

$2\sqrt{ab}-9\sqrt{ab}$

$\int\:\frac{5x^2+x+-2}{x^3+2x^2}\:dx$