## Elementary Algebra

$-\frac{1}{3x}$
We factor the expression in the denominator in order to cancel out common factors in the numerator and the denominator: Step 1: $\frac{9-x^{2}}{3x^{3}-27x}$ Step 2: $\frac{9-x^{2}}{-3x(9-x^{2})}$ Step 3: $\frac{1}{-3x}$ Step 4: $-\frac{1}{3x}$