A) \[y=2x\]
B) \[y=2x\]
C) \[y=x\]
D) \[y=-x\]
Correct Answer: A
Solution :
Let\[A=\left[ \begin{matrix} 1 & 2 & x \\ 3 & -1 & 2 \\ \end{matrix} \right]\]and \[B=\left[ \begin{align} & y \\ & x \\ & 1 \\ \end{align} \right]\] \[AB=\left[ \begin{matrix} 1 & 2 & x \\ 3 & -1 & 2 \\ \end{matrix} \right]\left[ \begin{align} & y \\ & x \\ & 1 \\ \end{align} \right]\]\[\Rightarrow \left[ \begin{align} & 6 \\ & 8 \\ \end{align} \right]=\left[ \begin{matrix} \begin{align} & y+2x+x \\ & 3y-x+2 \\ \end{align} \\ \end{matrix} \right]\] \[\Rightarrow \]\[y+3x=6\]and \[3y-x=6\] On solving, we get\[x=\frac{6}{5}\]and \[y=\frac{12}{5}\]\[\Rightarrow \]\[y=2x\]You need to login to perform this action.
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