So you get Y over four is equal to the square root of nine minus X. Now we can square both sides. Y squared over 16 is equal to nine minus X. And then let's see, we could multiply both sides by negative one. So negative Y squared over 16 is equal to X minus nine. And now we could add nine to both sides and we get nine minus Y squared over 16 is equal to X. And so we could substitute that right over there.