Basically, in each option, you have to find the relationship between x and y (for one pair). Like in option #1 - how do you get 1.5 from 3? divide it by 2. Now you apply it for all numbers. It the outcome the same? No. 7 ÷ 2 ≠ 3.
You do the same process for all, until you are left with the last one. y = 50x
