Q3 of 75 Page 8

Mark the correct alternative in the following:

Let and If AX = B, then X is equal to


Given that


X = , A = and B =


Also AX = B and we have to find the value of X ,


Pre-multiplying A-1 both sides we get,


A-1AX = A-1B


IX = A-1B ( A-1A = I )


X = A-1B ( IX = X) ……(i)


Now,


|A| = = 1(0-2) +1(2-3) +2(4-0) = -2-1+8 = 5


And adjA =


A-1 = adjA =


From (i),


= = =


=


On comparing both sides we get,


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