1. The problem asks us to develop (expand and simplify) the expression $$(\sqrt{7}-3)(\sqrt{7}+3)$$. 2. Notice this is a product of conjugates of the form $(a-b)(a+b)$ which equals $a^2 - b^2$. 3. Here, $a = \sqrt{7}$ and $b = 3$. 4. Apply the formula: $$a^2 - b^2 = (\sqrt{7})^2 - 3^2 = 7 - 9$$. 5. Simplify the result: $$7 - 9 = -2$$. 6. Therefore, the product $$(\sqrt{7}-3)(\sqrt{7}+3)$$ equals to $$\boxed{-2}$$.