How Do You Use the Formula for the Product of a Sum and a Difference?

These two binomials are exactly the same except for their signs
The formula for the product of a sum and difference gives us a shortcut so we don't have to FOIL
Both 4x² and 9 are perfect squares, which means we have a difference of squares

1. The formula for the product of a sum and difference is (a+b)(a-b)=a²-b²
1. 'a' is the first term in each binomial, which is 2x
2. 'b' is the second term in each binomial, which is 3
1. Plug '2x' in for 'a' and '3' in for 'b' into the formula for the product of a sum and difference
2. We get (2x+3)(2x-3)=(2x)²-(3)²
1. Square 2x to get 4x²
2. Square 3 to get 9
1. Since both 4x² and 9 are perfect squares, we have a difference of squares
2. You can use this formula in reverse as a shortcut to factoring a difference of squares
3. Just take the square root of each of the terms and plug them in for 'a' and 'b' in the left hand side of the formula

Expand the following: (2x + 3)(2x - 3)