$2x^4-12$

$\left(-a-5b\right)\left(-a+b\right)$

$\frac{\csc^2\left(x\right)-\sin^2\left(x\right)}{\csc\left(x\right)+\sin\left(x\right)}=\cos\left(x\right)\cdot\cot\left(x\right)$

$4x^2+7x+8$

$\left(3\sqrt{-4}+5\sqrt{9}\right)^5$

$19-\left(-38\right)$

$\frac{x^4-3x^2+2}{x-1}$