$\int\left(2x^3-8x+5\right)dx$

$\lim_{x\to9}\left(\frac{x-9}{x+9}\right)$

$12\left(3+\:y\right)\:=\:5\left(2y\:+\:8\right)$

$\lim_{x\to0}\left(\frac{cn-\cos\left(2x\right)}{7x^2}\right)$

$x+1\cdot x-1$

$49m^6-70mn^3n^2+25$

$\lim_{x\to0}\left(\frac{\left(\left(-19\right)^x\cdot x^2\right)}{x+21}\right)$