Question

Find the adjoint of the matrix $A=\left[\begin{array}{ccc}1& 2& 3\\ 1& 3& 5\\ 1& 5& 12\end{array}\right]$.
If $\text{Adjoint A:}\left[\begin{array}{ccc}a& -9& 1\\ b& 9& -2\\ 2& c& 1\end{array}\right]$, find the value of $abc$.

• A. 231
• B. 213
• C. 321
• D. 312

Answer 1

Answer: (A)

231