$\left(\left(\left(xy\right)^2x\right)^3y\right)^4$

$\lim_{x\to\infty}\left(\frac{6x-4}{6x+1}\right)^{3x}$

$\lim_{x\to0}\left(\frac{1-cosx\sqrt{cos2x}}{tan^2x}\right)^{\frac{1}{x^2}}$

$10a^2b^2-15a^3b^3c^2+5ab^4c^3$

$40-16+20-8$

$\frac{d}{dx}\left(\frac{\left(x+1\right)\left(3x+1\right)\left(2x+1\right)}{\sqrt{8x+1}}\right)$

$ax+by+ay+ax$