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If A is a square matrix and I is an identity matrix of same order such that $A^2=A$, then $(2I+A)^2 - 5A$ is |
O 4I 5A 2I |
4I |
The correct answer is Option (2) → 4I Given $A^{2}=A$ Compute $(2I+A)^{2}$ $(2I+A)^{2}=4I+4A+A^{2}$ Since $A^{2}=A$: $=4I+4A+A$ $=4I+5A$ Now compute $(2I+A)^{2}-5A$ $=4I+5A-5A$ $=4I$ $4I$ |
