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

$\frac{6x^4-9x-x^2-2}{x^2+1}$

$\left(2x^3+2y\right)\left(2x^3+2y\right)$

$cot^2\left(x\right)-\cot^2\left(x\right)\cos\left(2x\right)+2sen^2\left(x\right)=2$

$\left(2n^3-n^3\right)^3$

$2\:\left(x^2+2x-15\right)$

$\left(x+4\right)^{2}+\left(x+3\right)+x^{2}-3x-9$