SOLUTION: x-3y-z=-9 -2x+y+2z=3 2x+y+3z=8

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Question 173477: x-3y-z=-9
-2x+y+2z=3
2x+y+3z=8
Answer by solver91311(24713) About Me  (Show Source):
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Eq. 1 x-3y-z=-9
Eq. 2 -2x%2By%2B2z=3
Eq. 3 2x%2By%2B3z=8

Add Eq. 2 to Eq. 3:

Eq. 4 0x%2B2y%2B5z=11 → 2y%2B5z=11

Multiply Eq. 1 by 2:

Eq. 5 2x-6y-2z=-18

Add Eq. 2 to Eq. 5:

Eq. 6 0x-5y%2B0z=-15 → y=3

Substitute value for y in Eq. 4:

2y-5z=11 → 2%283%29-5z=11 → -5z=5 → z=-1

Substitute values for y and z in Eq. 1:

x-3y-z=-9 → x-3%283%29-%28-1%29=-9 → x-9%2B1=-9 → x=-1

So the solution set is the ordered triple (-1,3,-1)