2x+4y+2z=10 reduces to x + 2y + z = 5
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 <====
-x - z = 7
-x - 48 = 7
-x = 7 + 48
-x = 55
x = -55 <====
x + y + z = -1
-55 + y + 48 = -1
- 7 + y = -1
y = -1 + 7
y = 6 <====
so x = -55, y = 6, and z = 48
