Question 926828
x+2y+z=9, 
<u>-2(2x+y+3z=7 )</u>
-3x -5z = -5
{{{(-3/5)x + 1}}} = z
.........
x + 2y + (-3/5)x + 1 = 9
2y + (2/5)x  = 8
y = {{{(-2/10)x + 4}}}
(x, (-2/10)x + 4, (-3/5)x + 1) for all values of x
.....
x = 10
(10, 2, -5)
......
And...checking
x+2y+z=9
10 + 4 - 5 = 9