Question 904455:  x y-2z=7, 2x-3y-2z=0, x-2y-3z=3 How to solve this linear equation by using: Addition method and row equivalent method? 
 Found 2 solutions by  Fombitz, richwmiller: Answer by Fombitz(32388)      (Show Source):  Answer by richwmiller(17219)      (Show Source): 
You can  put this solution on YOUR website! I am guessing that it should be +y in the first equation 
The answers come out (23/3,22/3,10/-3) with -1y 
and (1,2,-2) with +1y
 
 x +y-2z=7, 
 2x-3y-2z=0, 
 x-2y-3z=3
 
1,1,-2,7 
2,-3,-2,0 
1,-2,-3,3
 
 
add  down (-2) *row 1 to row 2 
1,1,-2,7 
0,-5,2,-14 
1,-2,-3,3
 
add  down (-1) *row 1 to row 3 
1,1,-2,7 
0,-5,2,-14 
0,-3,-1,-4
 
divide row 2 by -5 
1,1,-2,7 
0,1,2/-5,-14/-5 
0,-3,-1,-4
 
add  down (3) *row 2 to row 3 
1,1,-2,7 
0,1,2/-5,14/5 
0,0,11/-5,22/5
 
divide row 3 by 11/-5 
1,1,-2,7 
0,1,2/-5,14/5 
0,0,1,-2
 
We now have the value for the last variable. 
We will work our way up and get the other solutions.
 
add up  (-2/-5) *row 3 to row 2 
1,1,-2,7 
0,1,0,2 
0,0,1,-2
 
add up  (2) *row 3 to row 1 
1,1,0,3 
0,1,0,2 
0,0,1,-2
 
add up  (-1) *row 2 to row 1 
1,0,0,1 
0,1,0,2 
0,0,1,-2
 
final 
1,0,0,1 
0,1,0,2 
0,0,1,-2
 
 
"1","2","-2" 
(1,2,-2)
 
 
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