​Solve the System of Linear Equations​ $$\left\{ \begin{array} { l l } 7 x + 7 y + 7 z & = 0 \\21 x + 35 y + 28 z & = 6 \\21 x + 42 y + 35 z & = 1\end{array} \right.$$

question 42

Multiple Choice

​Solve the system of linear equations​ $$\left\{ \begin{array} { l l } 7 x + 7 y + 7 z & = 0 \\21 x + 35 y + 28 z & = 6 \\21 x + 42 y + 35 z & = 1\end{array} \right.$$ ​using the inverse matrix $$\frac { 1 } { 7 } \left[ \begin{array} { c c c } 1 & 1 & - 1 \\- 3 & 2 & - 1 \\3 & - 3 & 2\end{array} \right]$$ .

• A)​ \[\left[ \begin{array} { l }
• x \\
• y \\
• z
• \end{array} \right] = \left[ \begin{array} { c }
• \frac { - 5 } { 7 } \\\\
• \frac { 11 } { 7 } \\\\
• \frac { - 12 } { 7 }
• \end{array} \right]\]
• B)​ \[\left[ \begin{array} { l }
• x \\
• y \\
• z
• \end{array} \right] = \left[ \begin{array} { c }
• \frac { 5 } { 7 } \\\\
• \frac { 11 } { 7 } \\\\
• \frac { - 16 } { 7 }
• \end{array} \right]\]
• C)​ \[\left[ \begin{array} { l }
• x \\
• y \\
• z
• \end{array} \right] = \left[ \begin{array} { c }
• \frac { 16 } { 7 } \\\\
• \frac { 5 } { 7 } \\\\
• \frac { 11 } { 7 }
• \end{array} \right]\]
• D)​ \[\left[ \begin{array} { l }
• x \\
• y \\
• z
• \end{array} \right] = \left[ \begin{array} { c }
• \frac { - 12 } { 7 } \\\\
• \frac { 11 } { 7 } \\\\
• \frac { - 5 } { 7 }
• \end{array} \right]\]
• E)​ \[\left[ \begin{array} { l }
• x \\
• y \\
• z
• \end{array} \right] = \left[ \begin{array} { c }
• \frac { - 5 } { 7 } \\\\
• \frac { - 16 } { 7 } \\\\
• \frac { 11 } { 7 }
• \end{array} \right]\]

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