## Elementary Algebra

$\frac{-2n-21}{n(n+3)}$
By inspection, we see that the LCM of the denominators is $n(n+3)$. Therefore, we create a common denominator using this LCM and obtain: $\frac{5}{n+3}-\frac{7}{n}$ =$\frac{n(5)-7(n+3)}{n(n+3)}$ =$\frac{5n-7n-21}{n(n+3)}$ =$\frac{-2n-21}{n(n+3)}$