Mathematics · 2024
JEE Main · 8 April 2024, Shift 1 · Q4
Let A= [2, a, 0; 1, 3, 1; 0, 5, b]. If A^3=4 A^2-A-21 I, where I is the identity matrix of order 3 × 3, then 2 a+3 b is equal to
Let $\displaystyle A=\left[\begin{array}{lll}2 & a & 0 \\ 1 & 3 & 1 \\ 0 & 5 & b\end{array}\right]$. If $\displaystyle A^3=4 A^2-A-21 I$, where $\displaystyle I$ is the identity matrix of order $\displaystyle 3 \times 3$, then $\displaystyle 2 a+3 b$ is equal to
Official answer
From NTA’s final answer key for this paper.
(2)
$\displaystyle -13$
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JEE Main 2024 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.