$\left(\sqrt{a}+\frac{1}{b}\right)\:\left(\sqrt{a}-\:\frac{1}{b}\right)$

$x\left(5x^2+4\right)^3$

$\int\frac{x^3+3x}{x^4-2+7x^2}dx$

$\int\frac{x-3}{x^3+x^2+3x}dx$

$\left(t+h\right)^4$

$\frac{2}{b+3}+\frac{3}{b-3}=\frac{2}{b+3}$

$\lim_{x\to2}\left(\frac{x-2\cos\left(\pi2\right)}{x^2-4}\right)$