$2\left(x-2\right)\left(x+1\right)^2-3\left(x-2\right)^2\left(x+1\right)$

$\frac{x^2+2}{x^2+1}$

$2x^2-5x=12$

$cos^244-sin^244$

$\left(1+\csc a\right)\left(1-\sin a\right)=\cot a\cdot\cos a$

$\lim\:_{x\to\:\infty\:}\left(\frac{\left(11x\right)}{11x+8}\right)^{4x}$

$9^2\cdot\left(-2\right)^2$