Show that the system of equations
$$\begin{array} { r }
x + 2 y + 3 z = 1
4 x + 5 y + 6 z = 1
7 x + 8 y + 9 z = 1
\end{array}$$
does not have a unique solution.
Show that the system of equations in part (a) is consistent. Interpret this situation geometrically.