For each of the following, determine if the vector b is a linear combination of the vectors in set S. If it is, find weights that make it so. If

it isn't, explain how you can tell. \text { 23. } S=\left\{\left[\begin{array}{r} 1 \\ 2 \\ -3 \end{array}\right], \quad\left[\begin{array}{r} 2 \\ 7 \\ -9 \end{array}\right]\right\} ; \quad \mathbf{b}=\left[\begin{array}{r} -1 \\ -3 \\ 8 \end{array}\right]