Đáp án:
$\begin{array}{l}
a)A = {x^2} + 2x + 1 - {y^2}\\
= {\left( {x + 1} \right)^2} - {y^2}\\
= \left( {x + 1 + y} \right)\left( {x + 1 - y} \right)\\
= \left( {94,5 + 1 + 4,5} \right)\left( {94,5 + 1 - 4,5} \right)\\
= 100.91\\
= 9100\\
b)B = {x^2} - {y^2} - 2y - 1\\
= {x^2} - \left( {{y^2} + 2y + 1} \right)\\
= {x^2} - {\left( {y + 1} \right)^2}\\
= \left( {x - y - 1} \right)\left( {x + y + 1} \right)\\
= \left( {93 - 6 - 1} \right)\left( {93 + 6 + 1} \right)\\
= 86.100\\
= 8600
\end{array}$
