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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?