This is a simple difference of squares, and you can just use FOIL, or just memorize the formula for these, specific, difference of square problems. Here's the formula:
[tex](a+b)(a-b) = a^2-b^2[/tex]
So, if we apply that formula to this, we have:
[tex](x+2)(x-2) = x^2-4[/tex]
If you want, you can check by using FOIL, which is what most people use.
