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If A is a square matrix such that $A^2=A$, then $(I+A)^3-7 A$ is equal to: |
A 3A I A - I |
I |
The correct answer is Option (3) → I $(I+A)^3-7 A$ so $A^3+3A^2I+3AI^2+I^3-7A$ as $A^2=A$, so $A^3=A.A^2=A.A=A^2=A$ so $A+3A+3A+I-7A$ $=I$ |
