Okay last one! I need help with this one anybody???

Answer:
-1-4x=y
Step-by-step explanation:
You know that if x=0 than y=-1 so one of the equations must have a -1 in it. So the only to possible equations are -1+4x=y and -1-4x=y.
Next try imputing the value -1 into the first equation to see if we get 3
-1+-4
-5≠3
So it must be the other equation -1-4x=y