x + y + 3z = -4 2x - z = -3 -x - y - 2z = 5 Since y is already eliminated from the second equation, eliminate y from the 1st and 2nd equations. We only need to add them term by term: x + y + 3z = -4 -x - y - 2z = 5 ---------------- z = 1 Next we sustitute in the 2nd original equation: 2x - z = -3 2x - 1 = -3 2x = -2 x = -1 Finally substitute in the 1st original equation: x + y + 3z = -4 -1 + y + 3(1) = -4 -1 + y + 3 = -4 2 + y = -4 y = -6 Solution is (x,y,z) = (-1,-6, 1) Edwin