(Solved): (1) Row-reduce the following matrix to find a row-equivalent matrix that is in reduced row-echelon ...

(1) Row-reduce the following matrix to find a row-equivalent matrix that is in reduced row-echelon form: $$\left[\begin{array}{rrrr}4& 5& 7& 0\\ ?1& 1& 5& 2\\ 4& 1& ?5& 6\\ 9& 5& ?3& 1\end{array}\right]$$ (2) Find a parametrization for the solution set of the following system of equations: $$\begin{array}{r}{x}_1+x_2?4x_6=1\\ x_2?5x_3+9x_6=2\\ x_4+6x_5=5\\ x_5?3x_6=5\end{array}$$ For example, a parametrization of the line through the points $$(2,0)$$ and $$(0,1)$$ would be $$(2?2t,t)$$.