$\cos\left(1+\tan^2x\right)=\sec\left(x\right)$

$2x^3-5x^2+x+1\:y=2$

$\lim_{x\to1}\left(x+\ln\left(x\right)\right)^{\frac{2}{x^2-x}}$

$\left(\frac{1}{2}y^{-2}+\frac{1}{2}y^2\:\:\:\:\right)$

$-4x\left(2\right)-8x+21$

$x^4+6x^3-x^2-6x$

$\left(3a\right)\cdot\left(8b\right)$