Hi there!
it is y=80x
As you can see if x=80y then if we say that y=5 then x would be 400. Yiu can also tell that the if the x=5 then the y would be 500 so this wouldn’t make sense.
For B, you can tell that if x is 2 then y would be 160 which is correct if you can see..
Now we know that is B but let find out the others...
If x=y+80 then y always have to change... if x was 2 then the y would be 89 and if the x was 3 than y would be 160.
D is also the same as A but it’s the opposite.. y would be 160 then x would be 2. When y turned into 240 then x would be 3. It changes just like A.
Therefore, the equation that best represent this relationship is y=80x..