$\left(8y^2-\frac{2}{3}x\right)\left(8y^2+\frac{2}{3}x\right)$

$\left(-\frac{1}{2}x^2y\right)\left(-\frac{10}{3}x^3\right)$

$\frac{s^2+6}{s^4+5s^3+2s^2}$

$\frac{\left(y+1\right)}{y^3+1}$

$\cot a\left(\cot a\right)=\cos^2a+\sin^2a$

$\lim_{x\to-1}\left(\frac{3x-9x^2}{2ln\left(-1-2x\right)-2}\right)$

$4x^3y^2:2x^3y$