please help Can you solve each system and type the correct code? please remember yo type in all caps with no spaces.

Answer:
C?EB
Step-by-step explanation:
1) the answer is- ( 3, - 1 ) so letter will be - C
2) not sure?
3) the answer is - ( 2, 3 ) so letter will be - E
4) the answer is - ( 3, 6 ) so letter will be - B
I'm sorry, maybe someone can get number 2 for you, I got the rest.
Goodluck!