$\left(x+5\right)\left(x+3\right)+\left(x+5\right)\left(x-3\right)-\left(x-5\right)\left(x+3\right)-\left(x-5\right)\left(x-3\right)$

$\lim_{x\to1}\left(\frac{sin2x}{sin3x}\right)$

$-6\sqrt{3}\cdot\left(\sqrt{\frac{2}{2}}\right)$

$\lim_{x\to\infty}\left(\frac{x-3}{9-x^2}\cdot x\right)$

$\frac{6}{v+3}=\frac{10}{v-9}$

$2x^2+3x=0$

$\frac{dy}{dx}=3x\left(4y+2\right)^2$