$\left(7^6\right)^8$

$\frac{2x^2.}{x^2+9}$

$-x-5\ge20$

$\frac{x^3+2x+1}{x+1}$

$\frac{1+\sin\left(2y\right)}{\cos\left(2y\right)}$

$\frac{\left(\frac{1}{6}a^2+\frac{1}{36}ab-\frac{1}{6}b^2\right)}{\frac{1}{3}a+\frac{1}{2}b}$

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