$6\sec\left(x\right)+8=2\sec\left(x\right)$

$9y^2+6yz+z^2$

$\left(\csc^2x-1\right)\sec\left(x\right)=\cot^2x\:\sec\left(x\right)$

$0=\left(xz+9\right)\left(xz-5\right)$

$\frac{d^2}{dx^2}\left(x\ln\left(1-2x\right)\right)$

$x^2-4x-8$

$\frac{x^2-2x-3}{2}+\ln\left(1+x\right)+\frac{1}{y}$