text: Do the matrix vector multiplication and demand AX=0. Then\n1x - 1y - 2z = 0 (eq.1)\n2x - 2y - 4z = 0 (eq.2)\n3x - 3y - 4z = 0\nThe first and last equations are identical. So you have only two equations.\nFrom (1) x = y + 2z  gives in (2)\n2(y + 2z) -2y - 4z = 0\nThis is true for all y and z.\nNow the solution is X = [y + 2z . y, z]\nin which y and z can be chosen as you like it.