$\frac{x^4-2x^3+3\:x-6}{x-3}$

$\left(-8a^2b\right)\left(-6a^3b^2+5a^2b^3-3\right)$

$\frac{\sin^2\left(x\right)+2\sin\left(x\right)+1}{\cos^2\left(x\right)}=\frac{1-\sin\left(x\right)}{1+\sin\left(x\right)}$

$3x^5+x^2$

$\frac{d}{dx}y+y^4=x$

$-5k\:+\:2\:+\:6k$

$-10x-5\leq20$