$3\left[2x+1\right]+2\left[x+3\right]$

$9a^2-13a-21=0$

$\int\:\frac{1}{\left(x+2\right)^2+4}dx$

$\sqrt{49n^6}$

$\lim_{x\to0}\left(\frac{9^x-5^x}{3x}\right)$

$\frac{\left(1-\cos\left(v\right)\right)\left(1+\cos\left(v\right)\right)}{\cos^2\left(v\right)}=\tan^2\left(v\right)$

$\frac{y^2-y\:}{y^2-1}$