$\left(5x^{3\:}y\right)\:\left(-4xy\right)$

$\left(7z^2\right)^2$

$x^2\left(x-3-3x^2\right)$

$\lim_{x\to\frac{\pi}{2}}\left(\frac{2x}{sin\left(x-\frac{\pi}{2}\right)}\right)$

$\ln\left(\frac{4x^4sin\left(-7x\right)}{3x-3}\right)$

$\sqrt{x}+\sqrt{x^5}-\sqrt{x^6}$

$\left(\frac{1}{5}x^2+2\right)\left(\frac{1}{5}x^2+3\right)$