$\lim_{x\to0}\left(\frac{x^3-x^2-x+1}{sin^2\left(\pi x\right)}\right)$

$\frac{\left(\left(\frac{2}{-\infty\:}\right)\right)}{\left(3+\frac{2}{-\infty\:}\right)}$

$4x^2+16x+7$

$\left(3a+7c\right)\left(3a-7b\right)$

$4^{-2}\cdot4^3$

$\lim_{x\to\pi}\left(sin4x\right)\left(cot6x\right)$

$3x^5+25x^3+125x$