$\frac{d^2}{dy^2}\left(-\frac{x}{y}\right)$

$-6\cdot2^{.1x}=100$

$\lim_{x\to3}\left(\frac{1}{x-3}-\frac{1}{x^2-2x-3}\right)$

$\lim_{x\to0}\left(\frac{\sqrt[3]{x}-1}{\sqrt{x}-1}\right)$

$\left(5x^3-8mn^2\right)^2$

$\sqrt{x}+\sqrt{y}=2a$

$\frac{dy}{dx}=2y+1\:;y\left(0\right)=3$