Question

If A = `[(1, 1, -1), (1, -2, 1), (2, -1, -3)]`, then (adj A)A = ______

विकल्प

• `[(9, 0, 0), (0, 9, 0), (0, 0, 9)]`

• `[(-11, 0, 0), (0, -11, 0), (0, 0, -11)]`

• `[(17, 0, 0), (0, 17, 0), (0, 0, 17)]`

• `[(-7, 0, 0), (0, -7, 0), (0, 0, -7)]`

Answer 1

If A = `[(1, 1, -1), (1, -2, 1), (2, -1, -3)]`, then (adj A)A = `underline([(9, 0, 0), (0, 9, 0), (0, 0, 9)])`

Explanation:

(adj A)A = |A| I_n

= `[(1, 1, -1), (1, -2, 1), (2, -1, -3)] [(1, 0, 0), (0, 1, 0), (0, 0, 1)]`

= `9[(1, 0, 0), (0, 1, 0), (0, 0, 1)]`

= `[(9, 0, 0), (0, 9, 0), (0, 0, 9)]`