$\frac{dy}{dx}=-\frac{x}{y^2}$

$\lim_{x\to-3}\left(4x^3+5x^2-3x+6\right)$

$\left(a^2-2a+5\right)\left(2-3a+a^2\right)$

$\left(7a^4bc^3\right)\left(7a^4bc^3+cd^5\right)$

$-4x^3+48x^2$

$\frac{x^{2}-0.09}{x-0.3}$

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