\[\left( b^{2} - 1 \right)\left( b^{2} + 1 \right) - \left( b^{2} + 2 \right)^{2} =\]
\[= b^{4} - 1 - b^{4} - 4b^{2} - 4 =\]
\[= - 4b^{2} - 5\]
\[При\ b = - 3:\]
\[- 4 \cdot 9 - 5 = - 36 - 5 = - 41.\]