Question 915502: 2x+4y-3z=25
-3x+5y+2z=-81
5x+9y-5z=46
can you please solve this and DO NOT use cramers rule? thanks!
Answer by richwmiller(17219)   (Show Source):
You can put this solution on YOUR website! 2,4,-3,25
-3,+5,+2,-81
5,+9,-5,46
divide row 1 by 2
1,2,-3/2,25/2
-3,5,2,-81
5,9,-5,46
add down (3) *row 1 to row 2
1,2,-3/2,25/2
0,11,-5/2,-87/2
5,9,-5,46
add down (-5) *row 1 to row 3
1,2,-3/2,25/2
0,11,-5/2,-87/2
0,-1,5/2,-33/2
divide row 2 by 11
1,2,-3/2,25/2
0,1,-5/22,-87/22
0,-1,5/2,-33/2
add down (1) *row 2 to row 3
1,2,-3/2,25/2
0,1,-5/22,-87/22
0,0,100/44,-900/44
divide row 3 by 25/11
1,2,-3/2,25/2
0,1,-5/22,-87/22
0,0,1,-9
We now have the value for the last variable.
We will work our way up and get the other solutions.
add up (5/22) *row 3 to row 2
1,2,-3/2,25/2
0,1,0,-6
0,0,1,-9
add up (3/2) *row 3 to row 1
1,2,0,-1
0,1,0,-6
0,0,1,-9
add up (-2) *row 2 to row 1
1,0,0,11
0,1,0,-6
0,0,1,-9
final
1,0,0,11
0,1,0,-6
0,0,1,-9
1,0,0,11
0,1,0,-6
0,0,1,-9
"11","-6","-9"
(11,-6,-9)
|
|
|
