x + y + z = -1...multiply by -2 x + 2y + z = 5 ---------------- -2x - 2y - 2z = 2 (result of multiplying by -2) x + 2y + z = 5 -----------------add -x - z = 7
-x + 6y - 3z = -53 x + y + z = -1....multiply by -6 ------------------ -x + 6y - 3z = -53 -6x - 6y - 6z = 6 ------------------add -7x - 9z = - 47
-7x - 9z = -47 -x - z = 7....multiply by -7 ----------------- -7x - 9z = -47 7x + 7z = -49 (result of multiplying by -7) -----------------add -2z = - 96 z = -96/-2 z = 48 <====