iran-konkur 2019 Q130

iran-konkur · Other · konkur-riazi_1398_specialized_new-curriculum Matrices Linear System and Inverse Existence
130- From the matrix relation $\begin{bmatrix} 3 & -1 & 1 \\ 4 & 0 & -2 \\ 1 & 2 & 0 \end{bmatrix} \begin{bmatrix} x \\ 2x \\ -1 \end{bmatrix} = 0$, $\begin{bmatrix} x & 2x & -1 \end{bmatrix}$, the nonzero value of $x$ is which of the following?
(1) $\dfrac{2}{9}$ (2) $\dfrac{3}{8}$ (3) $\dfrac{4}{9}$ (4) $\dfrac{3}{5}$
\textbf{130-} From the matrix relation $\begin{bmatrix} 3 & -1 & 1 \\ 4 & 0 & -2 \\ 1 & 2 & 0 \end{bmatrix} \begin{bmatrix} x \\ 2x \\ -1 \end{bmatrix} = 0$, $\begin{bmatrix} x & 2x & -1 \end{bmatrix}$, the nonzero value of $x$ is which of the following?

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(1) $\dfrac{2}{9}$ \hfill (2) $\dfrac{3}{8}$ \hfill (3) $\dfrac{4}{9}$ \hfill (4) $\dfrac{3}{5}$

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