SOLUTION: I can not figure out how to begin this problem let alone complete it. We are using the Gauss-Jordan Method. I refered to the website http://aspire.cs.uah.edu/textbook/gauss.html an

Algebra ->  Equations -> SOLUTION: I can not figure out how to begin this problem let alone complete it. We are using the Gauss-Jordan Method. I refered to the website http://aspire.cs.uah.edu/textbook/gauss.html an      Log On


   

Question 116853This question is from textbook mathematics with applications
: I can not figure out how to begin this problem let alone complete it. We are using the Gauss-Jordan Method. I refered to the website http://aspire.cs.uah.edu/textbook/gauss.html and the website http://math.uww.edu/~mcfarlat/141/141gauss.htm for assistance and thought I understood what i was doing but I can not get to the answer that is in the back of the book for this problem. The answer in the book is (1,0,-1)
The problem is as follows....
x+3y-6x=7
2x-y+2z=0
x+y+2z=-1
the first part I think I got
1 3 -6 7
2 -1 2 0
1 1 2 -1
Can you please help me.
Thank you so much!!!!!! This question is from textbook mathematics with applications

Found 2 solutions by scott8148, stanbon:
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
the object is to use row operations to get
1__0__0__x
0__1__0__y
0__0__1__z

subtracting the first row from the third row; and subtracting twice the first row from the second row gives
1__3__-6__7
0__-7__14__-14
0__-2__8__-8

dividing the second row by -7; and dividing the third row by -2 gives
1__3__-6__7
0__1__-2__2
0__1__-4__4

subtracting the second row from the third row; and subtracting 3 times the second row from the first row gives
1__0__0__1
0__1__-2__2
0__0__-2__2

subtracting the third row from the second row; and dividing the third row by -2 gives
1__0__0__1
0__1__0__0
0__0__1__-1

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The problem is as follows....
x+3y-6x=7
2x-y+2z=0
x+y+2z=-1
the first part I think I got
1 3 -6 7
2 -1 2 0
1 1 2 -1
-------------------
Subtract the 1st row from the 3rd
Multiply the 1st row by -2 and add to the 2nd
--------------------
1 3 -6 7
0 -7 14 -14
0 -2 8 -8
---------------
Divide thru the 3rd row by -2
Divide thru the 2nd row by -7
---------------
1 3 -6 7
0 1 -2 2
0 1 -4 4
-----------------------
Subtract the 2nd row from the 3rd
-----------------------
1 3 -6 7
0 1 -2 2
0 0 -2 2
----------------
Divide thru 3rd row by -2
----------------
1 3 -6 7
0 1 -2 2
0 0 1 -1
-------------------
Multiply 3rd row by 2 and add to 2nd row
Multiply 3rd row by 6 and add to 1st row
----------------------
1 3 0 1
0 1 0 0
0 0 1 -1
----------------------
Multiply 2nd row by -3 and add to 1st
---------------------
1 0 0 1
0 1 0 0
0 0 1 -1
--------------
x = 1
y = 0
z = -1
=============
Cheers,
Stan H.