$\left(2x^3y\right)dx+\left(x^4+y^4\right)dy=0$

$4x^2-4x+7$

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

$\sqrt{\frac{36}{9}}$

$\frac{-9}{x\left(x-3\right)}$

$\frac{2}{\left(x+2\right)^2}$

$\left(\frac{a^{3m-1}\cdot a^{2m-2}}{a^{4m-3}}\right)^n$