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Question
If \[\begin{vmatrix}2x + 5 & 3 \\ 5x + 2 & 9\end{vmatrix} = 0\]
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Solution
\[\begin{vmatrix}2x + 5 & 3 \\ 5x + 2 & 9\end{vmatrix} = 0\]
\[ \Rightarrow 9(2x + 5) - 3(5x + 2) = 0\]
\[ \Rightarrow 18x + 45 - 15x - 6 = 0\]
\[ \Rightarrow 3x + 39 = 0\]
\[ \Rightarrow 3x = - 39\]
\[ \Rightarrow x = \frac{- 39}{3} = - 13\]
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