$-12-\left(-20\right)-5+\left(-7\right)$

$u-5u^2$

$\frac{\cos\left(2x\right)}{\sin\left(x\right)}\:=\:\frac{\cot\:^2\left(x\right)-1}{\csc\left(x\right)}$

$x\frac{dy}{dx}=\frac{y-1}{y+1}$

$\frac{dx}{dt^2}=-\frac{1}{2}$

$\left(2x^2+5\right)^4$

$\left(2x-x^{-\frac{1}{2}}\right)\cdot\left(x^3+x^{\frac{1}{2}}\right)$