Find the difference 7/x^2-3x - 1/x^2-9

To solve this problem you must apply the proccedure shown below:

 1. You have the following expression given in the problem above:

 7/x^2-3x - 1/x^2-9

 2. When you factor the denominator, you obtain:

 7/x(x-3) - 1/(x+3)(x-3)
 

 3. By simplifying the expression, you obtain:

 3(2x+7)/x(x+3)(x-3)
 3(2x+7)/x(x^2-9)

 The answer is:  3(2x+7)/x(x^2-9)

This does not make sense

The answer would be 13.5 minutes.