$-\left(a-b\right).\left(b-a\right)$

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

$\lim_{x\to\frac{\pi}{3}}\left(\frac{\cos\left(x\right)-\frac{1}{2}}{x-\frac{\pi}{3}}\right)$

$\left(\left(\frac{5}{2}\cdot a^{-1}\cdot b^{-2}\right)\cdot\left(\frac{2}{5}\cdot a^4\cdot b\right)\right)^{-3}$

$-3\left(4x-2\right)-2x$

$\lim_{x\to0}-\frac{1}{\left(x-1\right)^2}$

$\int\:27x^3e^{3x}dx$