題組內容

6. Give the following system $\mathbf{Bx} = \mathbf{b}$ where $ \mathbf{B} = \begin{bmatrix} 1 & 1 \\ 2 & -3 \\ 0 & 0 \end{bmatrix}, \quad \mathbf{b} = \begin{bmatrix} 3 \\ 1 \\ 2 \end{bmatrix}. $

(c)(5%) Calculate the residual \( r(\hat{\mathbf{x}}) \)