$5x^8y^7-10x^7\:y^8$

$\frac{dy}{dx}=\frac{2x\left(1+e^y\right)}{e^y}$

$0\cdot2^{-23}$

$16\:-\:4\:x^2$

$4z+8y-2t+5t+8z-6y$

$\lim_{x\to2}\left(\frac{x-2}{x^2+x-2}\right)$

$\frac{\sin\left(x\right)}{\cos\left(x\right)+1}=\frac{\cos\left(x\right)+1}{\sin\left(x\right)}$