$\left(-12\right)\::\:4\:\cdot\:\left(-5\right)\:-20\::\:\left(-2\right)$

$\frac{1}{3}\:x\:+\:-1\:=\:1$

$\frac{dy}{dx}\left(x+\sqrt{y^2-x^2}\right)=y$

$\frac{2x^3-1}{4x}$

$4x^2+4y^2-12x+16y-5=0$

$\left(\tan^2\left(x\right)\right)\cos\left(x\right)\csc\left(x\right)$

$\frac{d}{dx}5y^4+5$