$4x\left(x\:+\:6\right)\:-\:5y\left(x\:+\:6\right)$

$\frac{d}{dx}\left(\frac{\left(7x^5cosx\right)}{\left(x-1\right)^{\frac{2}{3}}e^{x+1}}\right)$

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

$\lim_{x\to-1}\left(\frac{x^2-3x-4}{x^2+1}\right)$

$\frac{d}{dx}y=3x^2$

$\csc^2\left(a\right)-\csc^2\left(a\right)\cdot\sec^2\left(a\right)=-\sec^2\left(a\right)$

$x^4\cdot2x^{-3}$