MHT CET202616 April 2026Evening ShiftMathematicsMatricesActual
If A = bmatrix 2 & 3 5 & -2 bmatrix , B⁻¹ = bmatrix 1 5 & 2 5 2 5 & - 1 5 bmatrix , then (AB)⁻¹ =
Options
- A1 95 bmatrix 8 & -1 -1 & 12 bmatrix
- B1 95 bmatrix 12 & -1 -1 & 8 bmatrix
- C1 95 bmatrix -12 & 1 1 & -8 bmatrix
- D1 95 bmatrix -8 & 1 1 & -12 bmatrix
Correct answer
B. 1 95 bmatrix 12 & -1 -1 & 8 bmatrix
Step-by-step solution
Using the reversal law for the inverse of a product of matrices, we have: (AB)⁻¹ = B⁻¹A⁻¹ First, we find the inverse of matrix A . The determinant of A is: |A| = (2)(-2) - (3)(5) = -4 - 15 = -19 The adjugate of A is obtained by swapping the diagonal elements and changing the signs of the off-diagonal elements: adj (A) = bmatrix -2 & -3 -5 & 2 bmatrix Thus, A⁻¹ is given by: A⁻¹ = 1 |A| adj (A) = 1 -19 bmatrix -2 & -3 -5 & 2 bmatrix = 1 19 bmatrix 2 & 3 5 & -2 bmatrix We are given B⁻¹ = bmatrix 1 5 & 2 5 2 5 & - 1 5