$\frac{x}{3}-\frac{9}{x}$

$f\left(x\right)=\ln\left(\frac{x+6}{-x}\right)$

$\frac{1}{\left(z+i\right)\left(z+1\right)}$

$p\left(x\right)=x^3+x^4-4x^3+6x^2+x-7$

$\left(6ay+y^2\right)$

$\left(cos2x-1\right)^2=1$

$\csc\left(x\right)-\tan\left(x\right)\cos\left(x\right)$