solving by elimination

Question

x + 2y + 3z = 4

-3x + 2y + z = 12

-2x - 2y - 4z =14

Answer 1

x + 2y + 3z = 4

-3x + 2y + z = 12

4x+2z=-8

2z=-8-4x

z=-4-2x

-3x + 2y + z = 12

-2x - 2y - 4z =14

-5x-3z=26

-5x-3(-4-2x)=26

-5x+12+6x=26

x+12=26

x=14

z=-4-2x

z=-4-2(14)

z=-4-28

z=-32

x + 2y + 3z = 4

14+2y+3(-32)=4

14+2y-96=4

2y-82=4

2y=86

y=43

Check of work:

-2x - 2y - 4z =14

-2(14)-2(43)-4(-32)=14

-28-86+128=14

-114+128=14

14=14

-3x + 2y + z = 12

-3(14)+2(43)-32=12

-42+86-32=12

86-74=12

12=12