If $C$ is $6 \times 6$ and the equation $Cx =v$ is consistent for every $v$ in $R^6$, is it possible that for some $v$, the equation $Cx=v$ has more than one solution? Why or why not?
Since $Cx=v$ is consistent for every $v$ in $\Bbb R^6$ then by the invertible matrix theorem $C$ is invertible which implies that that each equation $Cx=v$ has a unique solution.
Surround your text in
**bold**, to write a math equation use, for example,