Question 1197030
This is not complete work and not finished:

row operation
<pre>
4   1   3   1
-4  -3  0   7
-22 -1  0  -8


E2=E2-3E3

4   1   3   1
-62   0  0 -31
22  1  0  8


switch E2 & E3

4   1   3   1
22  1   0   8
-62 0   0  -31


4   1   3   1
22  1   0   8
62 0   0   31
</pre>

{{{highlight(x=1/2)}}}


Use E2 and known x to find 
.
.
Not finished and not thoroughly checked for mistakes