#### Answer

\begin{array}{l}{\qquad A=\left[\begin{array}{ll}{1} & {2} \\ {3} & {4} \\ {5} & {1}\end{array}\right]}
\end{array}
The column vectors
\begin{array}{l}
{\qquad \mathbf{b}_{1}=\left[\begin{array}{l}{1} \\ {3} \\ {5}\\
\end{array}\right]}\\
{\qquad \mathbf{b}_{2}=\left[\begin{array}{l}{2} \\ {4} \\ {1}\\
\end{array}\right]}\end{array}

#### Work Step by Step

Given \begin{array}{l}{a_{1}=[1.2]} \\{a_{2}=[3.4]} \\ {a_{3}=[5.1]}\end{array}
So, The appropriate matrix for the given row vectors is:
\begin{array}{l}{\qquad A=\left[\begin{array}{ll}{1} & {2} \\ {3} & {4} \\ {5} & {1}\end{array}\right]}
\end{array}
The column vectors for this matrix are:
\begin{array}{l}
{\qquad \mathbf{b}_{1}=\left[\begin{array}{l}{1} \\ {3} \\ {5}\\
\end{array}\right]}\\
{\qquad \mathbf{b}_{2}=\left[\begin{array}{l}{2} \\ {4} \\ {1}\\
\end{array}\right]}\end{array}