Maharashtra BoardEnglish MediumSTD 12 ScienceMathsMatrics2 Marks
MCQ
If $A ^2- A + I =0$, then $A ^{-1}=$
A
$A^{-2}$
B
$A + I$
✓
$I - A$
D
$A - I$
✓
Answer
Correct option: C.
$I - A$
(C) $A^2-A+I=0$ $\Rightarrow A \cdot A - A + I =0$ $\Rightarrow A ^{-1} \cdot A \cdot A - A ^{-1} \cdot A+ A ^{-1} \cdot I =0$ $\Rightarrow A - I + A ^{-1}=0$ $\Rightarrow A ^{-1}= I - A$
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