$\frac{2}{3}x^2\:.\:\frac{3}{4}x$

$\left(a^2-6a+9\right)$

$\frac{x^2}{25}-\frac{y^2}{36}$

$\left|4\right|-\left|-2\right|$

$-\left\{3\:\left[4\left(3-4\right)+5\left(-2+2^3\right)+\left(5-7\right)+6\right]+\frac{12}{4}\left(5-\sqrt{36}\right)\right\}$

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

$r^2-r-1=0$