For the following matrix in reduced row echelon form, give the set of solutions to the corresponding system of equations. Let any free variables be r, s or t. For example, if the solution is x_1 = 2r + 1, x_2 = r, you would enter 2*r+1, r [1 0 0 0 1 0 1 0 0 -5 -4 0 0 0 1| 6 4 2]