(b+7)(b-7)-(6-7)^2

To simplify the expression \((b+7)(b-7)-(6-7)^2\), we will first tackle each part separately.

1. Calculate \((6-7)^2\): \[ 6 - 7 = -1 \quad \Rightarrow \quad (-1)^2 = 1 \]

2. Expand \((b+7)(b-7)\) using the difference of squares formula: \[ (b+7)(b-7) = b^2 - 7^2 = b^2 - 49 \]

3. Now, combine the results: \[ (b^2 - 49) - 1 \]

4. Subtract 1 from -49: \[ b^2 - 49 - 1 = b^2 - 50 \]

Thus, the simplified expression is: \[ \boxed{b^2 - 50} \]