Solve the inequality LaTeX:  \displaystyle \frac{5}{x^{2} - 9}<\frac{4}{x^{2} - 7 x + 12}

Getting zero on one side and factoring gives LaTeX:  \displaystyle \frac{5}{\left(x - 3\right) \left(x + 3\right)} - \frac{4}{\left(x - 4\right) \left(x - 3\right)}< 0 . This gives the least common denominator as LaTeX:  \displaystyle \left(x - 4\right) \left(x - 3\right) \left(x + 3\right) . Building each fraction to get the common denominator gives LaTeX:  \displaystyle \frac{5 x - 20 - (4 x + 12)}{\left(x - 4\right) \left(x - 3\right) \left(x + 3\right)} < 0 . Simplifying gives LaTeX:  \displaystyle \frac{x - 32}{\left(x - 4\right) \left(x - 3\right) \left(x + 3\right)}<0 . The inequality can change signs at the zeros of the numerator, LaTeX:  \displaystyle \left\{32\right\} , or the zeros of the denominator LaTeX:  \displaystyle \left\{-3, 3, 4\right\} . Making a sign chart gives: This gives the solution LaTeX:  \displaystyle \left(-3, 3\right) \cup \left(4, 32\right)