Answer:
[tex]f(x)=(3x+2)(3x-2)[/tex]
Step-by-step explanation:
To solve the exercise you must apply the proccedure shown below:
1. You can rewrite the following terms:
[tex]9x^{2}=[(3x)^{2}[/tex]
[tex]4=2^{2}[/tex]
2. Both are perfect squares, therefore, by the difference of squares:
[tex]a^{2}-b^{2}=(a+b)(a-b)[/tex]
3. Then, you can rewrite the quadratic equation as it is shown below:
[tex]f(x)=(3x+2)(3x-2)[/tex]