Expert: Richard J. Raridon - 12/8/2004

Question
Hi.  I am trying to solve this problem from the book and I just am having trouble compairing it to thier example.  I have several more like this one.  If you could help me with one, that would be awesome!

The directions say...

Solve the following system using one of the row echelon methods...

     x+4y-2z=0
     -2x-6y+5z=5
     3x+14y-4z=8

I understand that i need to change it to a matrix that looks like this...

        1,4,-2,0
        -2,-6,5,5
        3,14,-4,8


But after that.  I am so lost.

I appreciate any help you can give me.

Nicole.


Answer
I've never heard of row echelon but you can certainly use determinants to solve the equations.  First, evaluate the determinant
1 4 -2
-2-6 5
3 14 -4
that's the denominator, call it D.
To calculate x, evaluate
0 4 -2
5 -6 5
8 14 -4
and divide that by D
repeat for the middle column to evaluate y
and the right column to evaluate z