$\:exacta\left(2x\:-\:1\right)dx\:+\:\left(3y\:+\:7\right)\:dy\:=\:0$

$2n-3\cdot2n$

$\frac{1-1x-x^{0}}{\sqrt{x^{4}+1x}}$

$\left(x+y\right)\:x\:\left(x-y\right)$

$\lim_{x\to0.99}\left(\frac{x^3-1}{x-1}\right)$

$\frac{dy}{dx}\left(2\left(x^2+y^2\right)^2-25\left(x^2-y^2\right)\right)$

$\frac{3x^2-7x\sqrt{x}-\sqrt{x}+5}{x+1}$