If begin vmatix 2 amp -5 amp 3 x amp 1 amp 4 0 ... - JAMB Mathematics 2019 Question
If \(\begin{vmatix} 2 & -5 & 3 \ x & 1 & 4 \ 0 & 3 & 2 \end{vmatrix} = 132\), find the value of x.
A
5
B
8
C
6
D
3
correct option: b
\(\begin{vmatix} 2 & -5 & 3 \ x & 1 & 4 \ 0 & 3 & 2 \end{vmatrix} = 132\)
\(\implies 2 \begin{vmatrix} 1 & 4 \ 3 & 2 \end{vmatrix} - (-5) \begin{vmatrix} x & 4 \ 0 & 2 \end{vmatrix} + 3 \begin{vmatrix} x & 1 \ 0 & 3 \end{vmatrix} = 132\)
\(2(2 - 12) + 5(2x) + 3(3x) = 132\)
\(-20 + 10x + 9x = 132\)
\(19x = 152\)
\(x = 8\)
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