Question:medium

If $A = \begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix}$, then $A^2 - 5A - 2I =$

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Do not waste time manually multiplying $A \times A$! The trace ($\text{tr}(A)$) is $5$ and the determinant is $-2$. The identity $A^2 - (\text{tr }A)A + (\det A)I = O$ always holds.

Updated On: May 31, 2026

$O$
$I$
$A$
$2A$

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The Correct Option is A

Solution and Explanation

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If $A = \begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix}$, then $A^2 - 5A - 2I =$

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The Correct Option is A

Solution and Explanation

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