If A is a matrix and |A| ≠ 0, then solution of the equation XA = B is:
Correct Answer :
X = BА-1
Solution :
The correct option is X = BA-1.
Let's understand how we arrive at this solution step-by-step.
We are given the matrix equation:
XA = B
We are also given that , which means that the matrix A is non-singular. Since A is non-singular, its multiplicative inverse, denoted as A-1, exists.
To solve for X, we need to isolate it. In matrix algebra, division is not defined, so we must multiply by the matrix inverse. Since matrix multiplication is non-commutative (meaning in general), the order of multiplication is extremely important.
In our equation XA = B, the matrix A is multiplied on the right side of X. Therefore, to eliminate A, we must post-multiply (multiply from the right) both sides of the equation by A-1:
(XA)A-1 = BA-1
Using the associative property of matrix multiplication, we can regroup the terms on the left-hand side:
X(AA-1) = BA-1
By definition, multiplying a matrix by its inverse yields the identity matrix, I (i.e., ):
XI = BA-1
Since multiplying any matrix by the identity matrix leaves it unchanged (i.e., ), we get:
X = BA-1
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