$81a^{10}b^{8}-100c^{4}$

$\lim_{x\to\infty}\left(\frac{6x^2}{e^{8x}}\right)$

$\sqrt{10x^{-1}}$

$\left(23\right)-25-16\left(-2\right)-10$

$\left(b\:-\:1\right)\:\left(b\:-\:7\right)$

$2\left(1+3u\right)-\left(1-4u\right)$

$\frac{1+\cos\left(a\right)}{\sin\left(a\right)}+\frac{\sin\left(a\right)}{1+\cos\left(a\right)}=\frac{2}{\sin\left(a\right)}$