I don’t know what you mean by augmented matrix but I can answer your question.
We are going to use elimination method as it is simpler.
We add both equations to each other. This gives us x - 9y = -43
We move - 9y to the other side of the equation to isolate x. X=-43+9Y
Now we use this value and put it in an equation. -(-43 + 9y) - 3y = -17.
43 -12y = -17
-12y = -17-43.
-12y=-60
Y = 5
X=-43+9(5)
X=2
Check
-2 - 3(5) = -17
2(2)-6(5) = -26
It is correct.
Message me if you don’t understand :)