If x, y, z are nonzero real numbers, then the inverse of matrix is
A =
|A| = x × (y × z) = xyz
Since, |A| ≠ 0
A-1 exists
To find the inverse of a matrix we need to find the Adjoint of that matrix
For finding the adjoint of the matrix we need to find its cofactors
Let Aij denote the cofactors of Matrix A
Minor of an element aij = Mij �
a11 = x, Minor of element a11 = M11 = = (y × z) – (0 × 0) = yz
a12 = 0, Minor of element a12 = M12 = = (0 × z) – (0 × 0) = 0
a13 = 0, Minor of element a13 = M13 = = (0 × 0) – (0 × y) = 0
a21 = 0, Minor of element a21 = M21 = = (0 × z) – (0 × 0) = 0
a22 = y, Minor of element a22 = M22 = = (x × z) – (0 × 0) = xz
a23 = 0, Minor of element a23 = M23 = = (x × 0) – (0 × 0) = 0
a31 = 0, Minor of element a31 = M31 = = (z × 0) – (0 × 0) = 0
a32 = 0, Minor of element a32 = M32 = = (x × 0) – (0 × 0) = 0
a33 = z, Minor of element a33 = M33 = = (x × y) – (0 × 0) = xy
Cofactor of an element aij, Aij = (-1)i+j × Mij
A11 = (-1)1+1× M11 = 1 × yz = yz
A12 = (-1)1+2× M12 = (-1) × 0 = 0
A13 = (-1)1+3× M13 = 1 × 0 = 0
A21 = (-1)2+1× M21 = (-1) × 0 = 0
A22 = (-1)2+2 × M22 = 1 × xz = xz
A23 = (-1)2+3 × M23 = (-1) × 0 = 0
A31 = (-1)3+1 × M31 = 1 × 0 = 0
A32 = (-1)3+2 × M32 = (-1) × 0 = 0
A33 = (-1)3+3 × M33 = 1 × xy = xy
Adj A = =
A-1 = adj A / |A|
A-1 = /xyz
A-1 =
A-1 = =
The correct answer is A