$3x\left(5x^5-2x^4+4x\right)$

$\lim_{x\to\infty}\left(ln6x-ln\left(x+9\right)\right)$

$\frac{5x-7}{3}+\frac{8-5x}{6}=\frac{x+3}{4}$

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

$\left|\left(-8+7\right)-\left(-2\right)\right|\cdot\left(-2\right)$

$\frac{d}{dx}\left(y-cx^2=0\right)$

$\frac{d^3}{dx^3}\left(x^5+3x^{-2}+4x\right)$