$8.499+-7.8$

$\frac{d}{dx}\left(x^2+2y+3z^2=1\right)$

$\frac{x\left(x+4\right)}{x\left(x+4\right)+x\left(x+5\right)+4}$

$\frac{dy}{dx}=\frac{2y+4x}{2x}$

$\left(k-2\right)^2$

$e^y\cos\left(x\right)\frac{dy}{dx}=\tan\left(x\right)$

$\left(a+b\right)^2-\left(b-a\right)^2+\left(a-b\right)^2-a^2-4b^2$