# How do you simplify (5x) /(x^2 - 9)*(6x + 18) / (15x^3)?

the answer is $\frac{2}{{x}^{2} \left(x - 3\right)}$
first factor $\left({x}^{2} - 9\right)$ since it's a difference of two squares. then factor out $6 x + 18$ so at this point, you have: $\frac{5 x}{\left(x - 3\right) \left(x + 3\right)} \cdot \frac{6 \left(x + 3\right)}{15 {x}^{3}}$ now you see that you can cancel $\left(x + 3\right)$ since there's two of them. now you can divide $5$ into $15$ but now you can divide $3$ into the $6$ on top of it. at this point, you have $\frac{x}{x - 3} \cdot \frac{2}{{x}^{3}}$ as you can see, you can take out one $x$ from ${x}^{3}$ so that will only leave you with your answer