$\left(x-21\right)^2$

$\left(ex+y\right)dx+\left(ey+x\right)dy=0$

$\left(ax+p\right)^2$

$\left(\frac{1}{3}x+3y\right)^3$

$\sin\left(x\right)cos^2ydx\:+cos^2xdy$

$\int_0^{\frac{\pi}{2}}\left(cos\left(x\right)\cdot\sqrt{4+4\cdot\sin^2\left(x\right)}\right)dx$

$\frac{x^2}{9}-\frac{2xy}{3}+y^2$