$\int4\sqrt{5-x^2}dx$

$1-x=0$

$-207+21$

$\frac{d}{dx}\left(\frac{x\sqrt{x-7}}{\left(3x-8\right)^4}\right)$

$\int\left(\frac{sin\left(\frac{9}{x}\right)}{x^2}\right)dx$

$\frac{\cos\:\left(x\right)\sin\:\left(2x\right)+\cos\:\left(2x\right)\cdot\:\:2\sin\:\left(x\right)}{\sin\:\left(x\right)}$

$\left[\frac{\sqrt[3]{27a\:}\:\sqrt{b^{-3}\:a^{-\frac{1}{3\:}}\:b}}{\sqrt{b^{-1}}\sqrt{16a^2}}\right]^{-1}$