Answer: Most of them cross each other once so I am not sure which one is the answer (sorry)
Step-by-step explanation:
x+y=7 is parallel to 3x+3y=3 and -6x-6y=3
3x+y=-1 and 6x+2y=-2 have infinite solutions togther (both are on top of each other)
The rest of the ways cross each other once
