$\left(mn+1\right)\left(mn-1\right)$

$8a^2b+12ab-4a^3b^2-6a^5b^3-12a^2b^3$

$2y''+\left(x+1\right)y'+3y$

$\int x^3\left(16+4x^2\right)^{\frac{3}{2}}dx$

$\left(x+3\right)\left(x-3\right)+9>0$

$\frac{\left(3m+2n\right)^2+\left(3m-2n\right)^2}{9m^2+4n^2}$

$\frac{dy}{dx}=2+4x+10y$