$\lim_{x\to0}\left(\frac{sin\left(x\right)}{\sqrt{\frac{1-x}{x}}}\right)$

$64\cdot22$

$\left(u^2+7\right)\left(-1-x\right)$

$12x^3+107x^2+32x-448$

$4\left(1+a\right)^2-4\left(1+a\right)\left(b-1\right)-\left(b-1\right)^2$

$\left(4x^2-1\right)\left(7x^3+x\right)$

$81x^2-16x^6$