On the left, for every 1x you get 4y. You have to multiply both sides by the same digit, that is how the first solution is 3x and 12y. The answer to the first blank would be 9x and 36y because you follow the same rules. The second blank would be 10x and 40y.
Now onto the right. It’s the same thing but with a decimal. In case you can’t find out what the base answer is, you can find the greatest common factor between 2 numbers and that can be your base. In this case, the base ratio would be 1x and 18y. For the first blank it would be 2x and 36y because you multiplied both sides by 2.
The next blank is more difficult because it is a fraction. Since it’s .5 it’ll be easier than other decimal numbers. When im working with this I like to multiply by the whole number than add half to it. So I would multiply 2*18 and then add 9 to it. So the answers would be 2.5x and 45y