Question

Solve the system?

2x+y+z=9
-x-y+z=1
3x-y+z=9

Answer 1

(2x+y+z=9 )+(-x-y+z=1),Add
we have: x + 2z=10
(2x+y+z=9)+(3x-y+z=9) , Add
have: 5x +2z=18

time(-1)(x + 2z=10) = -x-2z=-10
keep: 5x +2z=18
(-x-2z=-10)+(5x +2z=18), Add
Have: 4x =8
x = 8/4
x = 2
2+2z=10
z= (10-2)/2
z =4
solve y :
2(2)+y+4=9
y = 9-8
y=1