$x2+14x$

$2\left(8+3x\right)+2\left(x\right)\le320$

$4+80y+400y^2$

$2\:cos\:x\:\cdot\:\:tan\:x\:-\:1\:=0$

$\lim_{x\to0}\left(\frac{\cos4x-3t}{\sen^{2}3x}\right)$

$9m^2+12m+4m$

$\frac{5}{6}\left(x^2\right)-\frac{2}{3}\left(y^2\right)+\frac{3}{4}\left(xy\right)-\frac{1}{2}\left(xy\right)-\frac{1}{6}\left(x^2\right)+\frac{1}{8}\left(y^2\right)\frac{5}{6}\left(xy\right)-\frac{1}{3}\left(x^2\right)+\frac{1}{4}\left(y^2\right)$