$\left(n-4\right)\left(n-2\right)$

$\frac{4x^2-9y^2}{2x-3y}$

$\frac{2\sin^2\left(x\right)}{2\tan\left(x\right)-2\sin\left(x\right)\cos\left(x\right)}=\frac{\cos\left(x\right)}{\sin\left(x\right)}$

$8x-2y-3z-6x-3y+9z$

$3x^2-16x-12=0$

$\left(y+4\right)dx+xdy=0$

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