$\frac{6x^2-24x-126}{x+3}$

$\int x\cot^2\left(x^2\right)dx$

$r^3-s^3$

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

$6x-12+\frac{1}{4}x^2-7x+8$

$\frac{\left(8v^2w^{-3}x^2\right)^2}{\left(2v^3w^2x^{-4}\right)^6}\cdot\left(-v^2w^3x^{-2}\right)^{-3}$

$-2\left(-3u-x+4\right)$