$\left(\left(\frac{7}{5}a-\frac{5}{2}\right)\right)\left(\frac{7}{5}a+\frac{5}{2}\right)$

$\lim_{x\to\infty}\left(\frac{e^x}{x}\right)^2$

$\left(4\cdot27\cdot5\right)^2$

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

$\frac{x^6}{x^4}$

$49x^2-25u^2$

$\left(2a+3b\right).\left(4a-2b\right)$