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Linear Algebra Row Reduction?

  • Thread starter SMA_01
  • Start date
  • #1
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Linear Algebra Row Reduction???

Homework Statement



This question is frustrating me, and I might be missing the obvious, I tend to make algebraic mistakes, but I don't know what I'm doing wrong here!

I'm trying to solve this system using row reduction:

x-5y+4z=-3
2x-7y+3z=-2
-2x+y+7z=-1

Note this does not have to be in reduced echelon form, just regular echelon form.





The Attempt at a Solution




Okay so I started like this:
Note: "l" indicated the bar representing "=" sign
1 -5 4 l -3
2 -7 3 l -2 --> I then used -2(2nd row)+1st row
-2 1 7 l -1 --> And 2(1st row)+ 3rd row

To get:

1 -5 4 l -3
0 3 -5 l 4
0 -9 15 l -7
I'm trying to remove the -9 in the third row but can't seem to do it without the 15 becoming zero.

Any help please?

Homework Statement





Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2
241
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HINT: Some problems have more then 1 solution, some don't have any. [what is yours case?]
 

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