Question 152176
write the system of linear equations represented by the augmented matrix. Use x,y,z and if necessary w,x,y,z for the variables. 
<pre>
|4  1  5  1| 6|
|1 -1  0 -1| 8|
|3  0  0  7| 4|
|0  0 11  5| 3|
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Put w's after the numbers in the first column:
Put x's after the numbers in the second column:
Put y's after the numbers in the third column:
Put z's after the numbers in the fourth column:

|4w 1x  5y 1z| 6|
|1w-1x  0y-1z| 8|
|3w 0x  0y 7z| 4|
|0w 0x 11y 5z| 3|

Put in + signs between terms if there's not a 
sign between them

|4w+1x+ 5y+1z| 6|
|1w-1x+ 0y-1z| 8|
|3w+0x+ 0y+7z| 4|
|0w+0x+11y+5z| 3|

Replace all the "|" after the z's with equal signs:

|4w+1x+ 5y+1z= 6|
|1w-1x+ 0y-1z= 8|
|3w+0x+ 0y+7z= 4|
|0w+0x+11y+5z= 3|

Erase all the terms with a 0 coefficient:

|4w+1x+ 5y+1z= 6|
|1w-1x    -1z= 8|
|3w       +7z= 4|
|      11y+5z= 3|

Erase all the 1 coefficients:

|4w+ x+ 5y+ z= 6|
| w- x    - z= 8|
|3w       +7z= 4|
|      11y+5z= 3|

Write as a system of equations:

{{{system(4w+ x+ 5y+ z= 6,w-x-z=8,3w+7z= 4, 11y+5z= 3)}}}

Edwin</pre>