4. (1 point) Find the set of solutions for the linear system $$ \begin{array}{r) -2 x_{1}+6 x_{2}+3 x_{3}=13 W } 6 x_{2}-7 x_{3}=-8 \end{array} $$ Use $\mathbf {s 1}, \mathbf {s 2}$, etc. for the free variables if necessary. \left(x_{1}, x_{2}, x_{3} ight)=(\longrightarrow \longrightarrow) )) $$ SP.SD.427 $$