###### Exercise 7

Consider the vectors

\begin{equation*}
\vvec_1 = \threevec{2}{3}{-1},
\vvec_2 = \threevec{-1}{2}{4},
\wvec_1 = \fourvec{3}{-1}{1}{0},
\wvec_2 = \fourvec{-2}{4}{0}{1}
\end{equation*}

and suppose that \(A\) is a matrix such that \(\col(A)=\span{\vvec_1,\vvec_2}\) and \(\nul(A) = \span{\wvec_1,\wvec_2}\text{.}\)

What are the dimensions of \(A\text{?}\)

Find such a matrix \(A\text{.}\)