$7^4\cdot7^{-2}$

$\left(\:b\:\:+\:\:\:3\right)\:\:\left(b-\:\:1\right)$

$\frac{\cot x}{-1+\csc x}-\frac{\csc x}{\cot x};\tan x$

$\lim_{x\to0}\left(\frac{\ln\left(3-x\right)}{x^2-4}\right)$

$\tan^2x-2\tan x=0$

$x\left(x+1\right)\left(x-1\right);\:x=3;$

$\left(2xb^3+6m^2x^2y\right)^3$