#[(0, 3, 2), (2, -1, -3), (2, 2, -1)] * [(x), (y), (z)] = [(4), (3), (7)]#
#L_3' := L_2 - L_3 : [2-2, -1-2, -3 +1] * [(x), (y), (z)] = 3 - 7#
#L_3' : [0, -3, -2] * [(x), (y), (z)] = -4#
#L_3'' = L_1 + L_4: [0, 3-3, 2-2] * [(x), (y), (z)] = 4 - 4#
This is true for all #(x, y, z) in mathbb{R}^3#
#L_1 Rightarrow z(y) = (4 - 3y)/2#
#L_2 Rightarrow 2x - y - 3 (4 - 3y)/2 = 3# and we want x(y).
#4x - 2y - 12 + 9y = 6#
#4x = 18 - 7y#
# [(x), (y), (z)] = [((18-7y)/4), (y), ((4 - 3y)/2)] = y [(-7/4), (1), (-3/2)] + [(18/4), (0), (4/2)] #
#y = 4t#