Question 34772:  Solve the following system of equations using Gaussian elimination (with a matrix) and back substitution, or by using Gauss-Jordan elimination.
 
3x + y - z = 0 
x + y = 2z = 6 
2x + 2y = 3z = 10 
 Found 2 solutions by  checkley71, richwmiller: Answer by checkley71(8403)      (Show Source):  Answer by richwmiller(17219)      (Show Source): 
You can  put this solution on YOUR website! if you mean  
3,1,-1,0 
1,1,+2,6 
2,2,+3,10
 
divide row 1 by 3/1 
1,1/3,-1/3,0 
1,1,2,6 
2,2,3,10
 
 
 
add  down (-1/1) *row 1 to row 2 
1,1/3,-1/3,0 
0,2/3,7/3,6 
2,2,3,10
 
 
 
add  down (-2/1) *row 1 to row 3 
1,1/3,-1/3,0 
0,2/3,7/3,6 
0,4/3,11/3,10
 
 
 
divide row 2 by 2/3 
1,1/3,-1/3,0 
0,1,21/6,9 
0,4/3,11/3,10
 
 
 
add  down (-4/3) *row 2 to row 3 
1,1/3,-1/3,0 
0,1,7/2,9 
0,0,-1,-2
 
 
 
divide row 3 by -1/1 
1,1/3,-1/3,0 
0,1,7/2,9 
0,0,1,2
 
 
 
add up  (-7/2) *row 3 to row 2 
1,1/3,-1/3,0 
0,1,0,2 
0,0,1,2
 
 
 
add up  (1/3) *row 3 to row 1 
1,3/9,0,2/3 
0,1,0,2 
0,0,1,2
 
 
 
add up  (-1/3) *row 2 to row 1 
1,0,0,0 
0,1,0,2 
0,0,1,2
 
 
final 
1,0,0,0 
0,1,0,2 
0,0,1,2
 
 
1,0,0,0 
0,1,0,2 
0,0,1,2
 
if you mean
 
3,1,-1,0 
1,1,-2,6 
2,2,-3,10
 
 
divide row 1 by 3/1 
1,1/3,-1/3,0 
1,1,-2,6 
2,2,-3,10
 
 
 
add  down (-1/1) *row 1 to row 2 
1,1/3,-1/3,0 
0,2/3,-5/3,6 
2,2,-3,10
 
 
 
add  down (-2/1) *row 1 to row 3 
1,1/3,-1/3,0 
0,2/3,-5/3,6 
0,4/3,-7/3,10
 
 
 
divide row 2 by 2/3 
1,1/3,-1/3,0 
0,1,-15/6,9 
0,4/3,-7/3,10
 
 
 
add  down (-4/3) *row 2 to row 3 
1,1/3,-1/3,0 
0,1,-5/2,9 
0,0,1,-2
 
 
 
divide row 3 by 1/1 
1,1/3,-1/3,0 
0,1,-5/2,9 
0,0,1,-2
 
 
 
add up  (5/2) *row 3 to row 2 
1,1/3,-1/3,0 
0,1,0,4 
0,0,1,-2
 
 
 
add up  (1/3) *row 3 to row 1 
1,3/9,0,-2/3 
0,1,0,4 
0,0,1,-2
 
 
 
add up  (-1/3) *row 2 to row 1 
1,0,0,-2 
0,1,0,4 
0,0,1,-2
 
 
final 
1,0,0,-2 
0,1,0,4 
0,0,1,-2
 
 
1,0,0,-2 
0,1,0,4 
0,0,1,-2
 
 
 
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