(b+3) (b-3)

The expression \((b+3)(b-3)\) is a difference of squares. You can expand this expression using the formula \( a^2 - b^2 = (a+b)(a-b) \).

Here, \(a = b\) and \(b = 3\). Therefore:

\[ (b+3)(b-3) = b^2 - 3^2 \]

This simplifies to:

\[ b^2 - 9 \]

So, \((b+3)(b-3) = b^2 - 9\).