Question

Example 2: Solve by elimination.
3x + y -z = 4
x + 2y + 2z = 5
4x + y - z = 3

Answer 1

Answer: (-1, 5, -2)

Explanation:

3x + y -z = 4

x + 2y + 2z = 5

4x + y - z = 3

3x + y -z = 4

x=-1

x + 2y + 2z = 5

(4x + y - z = 3)*2

8x + 2y - 2z = 6

x + 2y + 2z = 5

9x+4y=11

9(-1)+4y=11

-9+4y=11

4y=20

y=5

x + 2y + 2z = 5

-1+2(5)+2z=5

-1+10+2z=5

9+2z=5

2z=-4

z=-2