Divide $\frac{3x}{\left(x-1\right)\left(x+1\right)}$ by $\frac{3}{x^{2}-1}$ by multiplying $\frac{3x}{\left(x-1\right)\left(x+1\right)}$ by the reciprocal of $\frac{3}{x^{2}-1}$.
Divide $\frac{3x}{\left(x-1\right)\left(x+1\right)}$ by $\frac{3}{x^{2}-1}$ by multiplying $\frac{3x}{\left(x-1\right)\left(x+1\right)}$ by the reciprocal of $\frac{3}{x^{2}-1}$.