$\left(6x^2-3xy\right)^2$

$\left(\frac{5b^2}{6}-\frac{1}{5}\right)^2$

$\lim_{x\to\pi}\left(\frac{\left(x-\pi\right).\cos\left(x-\frac{3\pi}{2}\right)}{1-\sec\left(x-\pi\right)\:}\right)$

$9^{10}:9^9\cdot9+9^2:9^2-9$

$2x-2x$

$8\cdot3\cdot5$