(1) 3x - 2y - z = 14 (2) x - 3y - 3z = 8 (3) 2x - 4y - 2z = 8 Multiply equation (2) by -3 -3(x - 3y - 3z) = -3(8) -3x + 9y + 9z = -24 Add it to the equation (1) (1) 3x - 2y - z = 14 -3x + 9y + 9z = -24 ------------------- (4) 7y + 8z = -10 --- Multiply equation (2) by -2 -2(x - 3y - 3z) = -2(8) -2x + 6y + 6z = -16 Add it to the equation (3) (3) 2x - 4y - 2z = 8 -2x + 6y + 6z = -16 ------------------- 2y + 4z = -8 Divide that through by 2 (5) y + 2z = -4 Now we have a system of 2 equations with only 2 unknowns: (4) 7y + 8z = -10 (5) y + 2z = -4 Multiply eq. (5) by -4 -4(y + 2z) = -4(-4) -4y - 8z = 16 add that to eq (4): (4) 7y + 8z = -10 -4y - 8z = 16 -------------- 3y = 6 y = 2 Substitute in eq (4) 7(2) + 8z = -10 14 + 8z = -10 8z = -10-14 8z = -24 z = -3 Substute y = 2 and z = -3 in eq. (1) (1) 3x - 2y - z = 14 3x - 2(2) - (-3) = 14 3x - 4 + 3 = 14 3x - 1 = 14 3x = 15 x = 5 So the solution (x,y,z) = (5,2,-3) Edwin