We shall first find the point of intersection of the line 2x+y=2 and (x+2y=1) , as follows:
2x+y=2 - - - - - (1)
x+2y=1 - - - - - (2)
2 × (2) gives 2x+4y=2 - - - - - (3)
(1) - (3) gives: −3y=0
⟹y=0
Substituting y=0 in (1), we get x=1.
∴ Point of intersection is (1,0).
Putting this point in the L.H.S. of x+y=1, we get,
1+0
= 1
= R.H.S.
Hence all the given lines pass through the same point.