$\frac{x\:-\:4}{x^2\:-\:8x\:+\:16}$

$\left(8a-7b\right)^2$

$3x^2-7x=2x^2-12$

$\lim_{x\to0}\left(\frac{\sqrt{9+x}-3}{x^2+3}\right)$

$\left(7a^4b^3-cd5\right)\left(7a^4b^3+cd^5\right)$

$\frac{\left(m-4\right)}{\left(m-1\right)}=\frac{12}{\left(m-3\right)}$

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