If A=⎡⎢⎣12221−2a2b⎤⎥⎦ is a matrix satisfyingAAT=9I3, then find the values of a and b.

If A=⎡⎢⎣12221−2a2b⎤⎥⎦ is a matrix satisfyingAAT=9I3, the

1.	If A=⎡⎢⎣12221−2a2b⎤⎥⎦ is a matrix satisfyingAAT=9I3, then find the values of a and b.
Answer» If $A = ⎡ ⎢ ⎣ \begin{matrix} 1 & 2 & 2 2 & 1 & - 2 a & 2 & b \end{matrix} ⎤ ⎥ ⎦$ is a matrix satisfying $A A^{T} = 9 I_{3}$ , then find the values of $a$ and $b$ .