Question

The sum of three numbers is 6. Twice the third number, when added to the first number gives 7. On adding the sum of the second and third numbers to thrice the first number, we get 12. The above situation can be represented in matrix form as \( AX = B \). Then \( | \text{adj } A | \) is equal to

• A. \( -4 \)
• B. 4
• C. \( -64 \)
• D. 16

Hint:

For an \(n \times n\) matrix, \( |\text{adj } A| = |A|^{n-1} \). For \(3 \times 3\), it becomes \( |A|^2 \).

Answer 1

The Correct Option is D