$2cos\left(\frac{1}{6}x\right)=\sqrt{3}$

$\sqrt[2a]{\frac{\left(21\right)^{2a+1}}{7^{2a+1}\cdot3}}$

$\frac{x^3-2x^2-11x+12}{x+2}$

$\lim_{x\to\infty}\left(\sqrt{x^6+5x^3}-x^3\right)$

$\left(\cos\left(x\right)-\csc\left(x\right)\right)\left(\cos\left(x\right)+1\right)$

$-5-7-6+5$

$2.5+7.5-9.26$