Question:medium
Let $A$ be a non-singular square matrix of order 3. If $A^2 - A = 20I$, where $I$ is the unit matrix of order 3, then $A^{-1} =$}
Let $A$ be a non-singular square matrix of order 3. If $A^2 - A = 20I$, where $I$ is the unit matrix of order 3, then $A^{-1} =$}
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When asked for $A^{-1}$ given a polynomial equation in $A$, factor $A$ out and use the definition $A \cdot (\text{something}) = I$ to identify the inverse immediately.
Updated On: Jun 24, 2026
- $20A$
- $\frac{1}{20}(A - I)$
- $20(A - I)$
- $\frac{1}{20}A$
- $\frac{1}{20}A^2$
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The Correct Option is B
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