\text { Suppose } \vec{x}=\left(\begin{array}{l} 1 \\ 1 \\ 1 \\ 1 \end{array}\right) \text { solves } A \vec{x}=\vec{b}, A \text { is a diagonal matrix, and } \operatorname{tr}(A)=7 \text

{ . Find }(2 \quad 2 \quad 2 \quad 2) \vec{b} \text { . }