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Find the Value of X, If ∣ ∣ ∣ 3 X X 1 ∣ ∣ ∣ = ∣ ∣ ∣ 3 2 4 1 ∣ ∣ ∣

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Question

Find the value of x, if

\[\begin{vmatrix}3 & x \\ x & 1\end{vmatrix} = \begin{vmatrix}3 & 2 \\ 4 & 1\end{vmatrix}\]

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Solution

\[\text{ Given }: \begin{vmatrix}3 & x \\ x & 1\end{vmatrix} = \begin{vmatrix}3 & 2 \\ 4 & 1\end{vmatrix}\]
\[ \Rightarrow 3 - x^2 = 3 - 8\]
\[ \Rightarrow - x^2 = - 8\]
\[ \Rightarrow x^2 = 8\]
\[ \Rightarrow x = \pm 2\sqrt{2}\]

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Chapter 5: Determinants - Exercise 6.1 [Page 10]

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R.D. Sharma Mathematics Volume 1 and 2 [English] Class 12
Chapter 5 Determinants
Exercise 6.1 | Q 10.3 | Page 10

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