Consider three planes `P_1 : x-y + z = 1`, `P_2 : x + y-z=-1` and `P_3 : x-3y + 3z = 2` Let `L_1, L_2` and `L_3` be the lines of intersection of the planes `P_2 and P_3`, `P_3 and P_1` and `P_1 and P_2` respectively.Statement 1: At least two of the lines `L_1, L_2 and L_3` are non-parallel The three planes do not have a common point