$-72\left(822\right)$

$x^2+18xy+81y^2$

$\frac{d}{dx}\sqrt[5]{x^2+3x-\frac{3}{x}}$

$\frac{x^2+2x+1}{x}$

$-\:\left\{-20\:-\:-4\:-\:\left[-8\:+\:\left(+12\:-6\:-2\right)\:+2\:+3\right]\right\}-\:-4\:-\:\left[-8\:+\:\left(+12\:\:-2\right)\:+2\:+3\right]$

$x+1=2x+6$

$\lim_{x\to0}\left(\frac{\log\left(\sin\left(7x\right)\right)}{\log\left(\sin\left(x\right)\right)}\right)$