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Determinants — Maths STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceMathsDeterminants1 Mark
MCQ
For what value of $x$, matrix $A=\left[\begin{array}{ll}6-x & 4 \\ 3-x & 1\end{array}\right]$ is a singular matrix?
  • A
    1
  • ✓
    2
  • C
    -1
  • D
    -2
✓

Answer

Correct option: B.
2
(b) : Matrix $A$ is singular, when $|A|=0$
$\Rightarrow\left|\begin{array}{ll}6-x & 4 \\ 3-x & 1\end{array}\right|=0$
$\Rightarrow 6-x-12+4 x=0 \Rightarrow 3 x=6 \Rightarrow x=2$

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