<exercise checkit-seed="0009" checkit-slug="V2" checkit-title="Linear combinations">
<statement>
<p>Consider the following statement.</p>
<ul>
<li>
The vector <m> \left[\begin{array}{c}
1 \\
3 \\
6 \\
-10
\end{array}\right] </m>is not
a linear combination of the vectors <m> \left[\begin{array}{c}
-1 \\
-1 \\
4 \\
2
\end{array}\right] , \left[\begin{array}{c}
0 \\
-2 \\
2 \\
-1
\end{array}\right] , \left[\begin{array}{c}
3 \\
2 \\
4 \\
2
\end{array}\right] , \left[\begin{array}{c}
-7 \\
-9 \\
0 \\
-4
\end{array}\right] , \text{ and } \left[\begin{array}{c}
-6 \\
2 \\
-14 \\
-1
\end{array}\right] </m>.
</li>
</ul>
<ol>
<li> Write an equivalent statement using a vector equation.</li>
<li> Explain why your statement is true or false.</li>
</ol>
</statement>
<answer>
<me>\operatorname{RREF} \left[\begin{array}{ccccc|c}
-1 & 0 & 3 & -7 & -6 & 1 \\
-1 & -2 & 2 & -9 & 2 & 3 \\
4 & 2 & 4 & 0 & -14 & 6 \\
2 & -1 & 2 & -4 & -1 & -10
\end{array}\right] = \left[\begin{array}{ccccc|c}
1 & 0 & 0 & 1 & 0 & 0 \\
0 & 1 & 0 & 2 & -3 & 0 \\
0 & 0 & 1 & -2 & -2 & 0 \\
0 & 0 & 0 & 0 & 0 & 1
\end{array}\right] </me>
<ol>
<li>
The vector equation <m> x_{1} \left[\begin{array}{c}
-1 \\
-1 \\
4 \\
2
\end{array}\right] + x_{2} \left[\begin{array}{c}
0 \\
-2 \\
2 \\
-1
\end{array}\right] + x_{3} \left[\begin{array}{c}
3 \\
2 \\
4 \\
2
\end{array}\right] + x_{4} \left[\begin{array}{c}
-7 \\
-9 \\
0 \\
-4
\end{array}\right] + x_{5} \left[\begin{array}{c}
-6 \\
2 \\
-14 \\
-1
\end{array}\right] = \left[\begin{array}{c}
1 \\
3 \\
6 \\
-10
\end{array}\right] </m>has no solutions.</li>
<li>
<p><m> \left[\begin{array}{c}
1 \\
3 \\
6 \\
-10
\end{array}\right] </m> is not
a linear combination of the vectors <m> \left[\begin{array}{c}
-1 \\
-1 \\
4 \\
2
\end{array}\right] , \left[\begin{array}{c}
0 \\
-2 \\
2 \\
-1
\end{array}\right] , \left[\begin{array}{c}
3 \\
2 \\
4 \\
2
\end{array}\right] , \left[\begin{array}{c}
-7 \\
-9 \\
0 \\
-4
\end{array}\right] , \text{ and } \left[\begin{array}{c}
-6 \\
2 \\
-14 \\
-1
\end{array}\right] </m>.
</p>
</li>
</ol>
</answer>
</exercise>