$14^4\cdot14^{-2}$

$\frac{dy}{dx}=\frac{7x}{4y}$

$x'=x\left(1-x\right)\left(x-2\right)$

$15ab-9ab-25x^2y+312x^2y$

$\lim_{x\to\frac{\pi}{6}}\left(\frac{\sin\left(x-\frac{\pi}{6}\right)}{\sqrt{3}-2\cos\left(x\right)}\right)$

$[\left(a^{3}-a\right)+\left(a^{2}-3\right)]\left(a^{3}-a\right)-\left(a^{2}-3\right)]$

$\left(8x-y\right)-5x\left(8x-y\right)$