$\lim_{x\to1}\left(\frac{\left(x^2-1\right)^2}{1-\cos\left(x-1\right)}\right)$

$\left(a+3\right)\left(a-1\right)$

$a^3b\left(a^3b+a^2b^3\right)$

$\lim_{x\to-2}\left(\frac{x^2-4}{x}\right)$

$\left(\frac{2x+1}{\left(x-1\right)^3\left(x^2+4\right)^2}\right)$

$\left(6f-4\right)\left(2f+8\right)$

$1-3+40-23+2$