$4m^2-81$

$4+\left(5+3\right)+5^2$

$-x^6\::\:3x^6$

$\frac{d}{dx}\left(\left(y-c\right)^2-2\left(x-b\right)\right)$

$\sin^3\left(x\right)+\sin\left(x\right)\cos^2\left(y\right)=\sin\left(x\right)$

$\left(10st+s^2v^3\right)\left(10st-s^2v^3\right)$

$3.2\sqrt{18}$