# Thread: Summer Math Problem driving me crazy

1. ## Summer Math Problem driving me crazy

This is a pre-calculus review to help me get ready for ap calc. I could not simplify the expression so I entered it into wolfram mathematica. I don't understand its second step though. If you could explain wolfram's steps or explain an easier method that would be great.

Here is the expression entered on wolfram: http://www.wolframalpha.com/input/?i=simplify+(9-(x^-2))/(3%2B(x^-1))

2. $\frac{{9 - \displaystyle\frac{1}
{{x^2 }}}}
{{3 - \displaystyle\frac{1}
{x}}} = \frac{{\left( {9 - \displaystyle\frac{1}
{{x^2 }}} \right)x^2 }}
{{\left( {3 - \displaystyle\frac{1}
{x}} \right)x^2 }} = \frac{{9x^2 - 1}}
{{3x^2 - x}} = \frac{{\left( {3x - 1} \right)(3x + 1)}}
{{x(3x - 1)}} = \frac{{3x + 1}}
{x}$

3. thank you. you are my hero.