Question 172106
Could you please show me how to do matrix for these equations? I don't understand how it works. 
7x+8y-z=9
x-2y-5z=-31
-7x+y+z=0 
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I can do that, but it's tedious to do on this site.
If you email me at gsihoutx@aol.com, I can scan and email you some hand-written notes, and an Excel sheet that I made that will solve 3x3 and 4x4 matrices.