Q8 of 108 Page 100

If show that A2 – 5A + 7I =0.

To prove: A2 – 5A + 7I = 0

Given: A =


L.H.S: A2 – 5A + 7I


R.H.S = 0


I =


Calculating value of A2:


A2 = A.A


=


=


=


=


Substituting value in L.H.S we get,


= A2 – 5A + 7I


.





= 0 = R.H.S


L.H.S = R.H.S


Hence A2 – 5A + 7I = 0 is proved.


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