Question 235195
1.)2x - y + z = 1
2.)x + 2y -4z = 3
3.)4x +3y -7z =-8
:
Multiply the 1st equation by 2 and add to the 2nd equation
4x - 2y + 2z = 2
 x + 2y - 4z = 3
-------------------addition eliminates y
5x - 2z = 5
;
Multiply the 1st equation by 3 and add to the 3rd equaiont
6x - 3y + 3z = 3
4x + 3y - 7z = -8
--------------------addition eliminates y again
10x - 4z = -5
:
You can see right now that this system has no solution
If you multiply eq 4 by 2 and add to the above, you can see
10x - 4z = 10
10x - 4z = -5
:
No wonder you were having trouble