If B = 5 2 α 1 0 2 1 α 3 - 1 is the inverse of a 3 × 3 matix A , then the sum of all values of α for which d e t A + 1 = 0 , is:

Question

If B = 5 2 α 1 0 2 1 α 3 - 1 is the inverse of a 3 × 3 matix A , then the sum of all values of α for which d e t A + 1 = 0 , is:, 2, 1, 0, - 1

MARKS App · Accepted Answer

Since, A = - 1 Hence, B = 1 | A | = - 1 ⇒ B = 5 - 5 - 2 α - α - 2 α = 2 α 2 - 2 α - 25 1 + A = 0 α 2 - α - 12 = 0 Sum = 1