(a) Find the reduced row echelon form of the matrix $M$. Your answers must be fractions (decimals are not allowed). $$M = \left[\begin{array}{cccc} -3 &1 &-3 &3\cr 4 &-3 &2 &-1 \end{array}\right].$$


(b) Solve the system $$\left\lbrace \begin{array}{rcr} -3x_{1}+x_{2} & = & -3 \\ 4x_{1}-3x_{2} & = & 2 \end{array} \right.$$ $\vec{x} =$ $\left[\Rule{0pt}{2.4em}{0pt}\right.$$\left]\Rule{0pt}{2.4em}{0pt}\right.$.

(c) Solve the system $$\left\lbrace \begin{array}{rcr} -3x_{1}+x_{2} & = & 3 \\ 4x_{1}-3x_{2} & = & -1 \end{array} \right.$$ $\vec{x} =$ $\left[\Rule{0pt}{2.4em}{0pt}\right.$$\left]\Rule{0pt}{2.4em}{0pt}\right.$.