Answer:
2
Step-by-step explanation:
Answer:
4x+y=12
Step-by-step explanation:
its the only one that is positive
and this is guess so don’t hate me if its wrong
hope this is right
Just do a line crossing another in a angle of 90°
1 is linear pair with 2, 2 is linear pair with 3, 3 is linear pair with 4 and 4 is linear pair with 1.