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Question
Find the value of x, if
\[\begin{vmatrix}x + 1 & x - 1 \\ x - 3 & x + 2\end{vmatrix} = \begin{vmatrix}4 & - 1 \\ 1 & 3\end{vmatrix}\]
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Solution
\[\text{ Given }: \begin{vmatrix}x + 1 & x - 1 \\ x - 3 & x + 2\end{vmatrix} = \begin{vmatrix}4 & - 1 \\ 1 & 3\end{vmatrix}\]
\[ \Rightarrow \left( x + 1 \right)\left( x + 2 \right) - \left( x - 3 \right)\left( x - 1 \right) = 12 + 1\]
\[ \Rightarrow x^2 + 3x + 2 - x^2 + 4x - 3 = 13\]
\[ \Rightarrow 7x - 1 = 13\]
\[ \Rightarrow 7x = 14\]
\[ \Rightarrow x = 2\]
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