$\lim_{x\to5}\left(\frac{x^2-25}{x^2-15x+50}\right)$

$\frac{dy}{dx}=\frac{x^2-6y^2}{2xy}$

$\frac{x+9}{5}=2$

$\int\frac{arctan\left(4y\right)}{1+16y^2}du$

$3\cdot\left(-3\right)\cdot\left(-2\right)$

$\frac{8x^3-43x^2-25x-30}{x-4}$

$\left(x-1\right)^2\left(x+2\right)^{3\:}\left(x^2+4\right)$