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Determinants — Maths STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceMathsDeterminants1 Mark
MCQ
If $\left[\begin{array}{cc}x & 2 \\ 18 & x\end{array}\right]=\left[\begin{array}{cc}6 & 2 \\ 18 & 6\end{array}\right]$ then $x$ is equal to :
  • A
    6
  • ✓
    $\pm 6$
  • C
    -6
  • D
    $0$
✓

Answer

Correct option: B.
$\pm 6$
(B)$\pm 6$
$x^2-36=36-36 \Rightarrow x^2-36=0$
or $x^2=36 \Rightarrow x=\sqrt{36}= \pm 6$

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