$\lim_{x\to0}\left(\frac{1-\cos6\left(x\right)}{x^2}\right)$

$y^2-139y-140$

$\int\:\frac{4}{3}x^2dx$

$\int_0^{-1}\left(10x^3-24x\right)^8\left(30x^2-24\right)dx$

$\left(\frac{1}{5}r-\frac{3}{4}r\right)^2$

$5x^2+1x\:+5\:per\:a\:x$

$\frac{x+1}{x-1}-\frac{2}{x^2-x}=\frac{4}{x}$