Basic Maths Grand Test- Q6

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If A is a square matrix such that A^2 = A , then (I+A)^3 - 7A $ equals

A. I-A

B. I

C. A

D. 3A

asked Nov 17 in Basic Maths by gbmentor (85,520 points)
reshown Nov 20 by getgatebook

1 Answer

0 votes

ANS should be B.

(I+A) ^3= I^3 + A^3 + 3I^2A + 3IA^2 = I + A + 3A + 3A = I+ 7A     [ A^2= A, A^3= A^2 *A= A^2= A]

Therefore=  I +7A - 7A=  I

answered Nov 20 by bhargavakapilpro20 (13,760 points)
Answer:
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