$\left(a-2b\right)^2-\left(x+y\right)^2$

$\frac{d^2y}{dx2}\left(3x^2+y-8xy\right)$

$\left(x-2\right)^4-\:\left(y+3\right)^4\:\:$

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

$4x^2+8x+49$

$\left(14x+9\right)-\left(8x+2\right)$

$\frac{dy}{dx}=\frac{\left(yln\left(x^y\right)\right)}{x}$