-4y = 3 - 2y
+2y = +2y
----------------
-2y = 3
---- ---
-2 -2
Y= -1.5
So your goal is to get x all alone
To achieve this you would have to add 2y to both sides to become -2y = 3
Then you would have to divide both sides by -2 (so y is all alone)
When you divide it it comes out to be y = -1.5