$-3\cdot3+2\cdot2$

$7x^2-3xy-2y^2\:-9x^2+2xy+4y^2$

$1\:\:0\:\:\:-12\:\:\:\:\:\:\:16\:$

$10x-y+10x+y$

$\frac{d^2}{dx^2}\left(5x^5-8x^2\right)$

$x\frac{dy}{dx}-y-x\cos\left(\frac{y}{x}\right)=0$

$\lim_{x\to0}\left(\frac{x\cdot\sin\left(x\right)}{2-2\cos\left(x\right)}\right)$