Need help with impDif and using previous value of y

[SpaceAlien]

I am wanting to do implicit differentiation of something simple like 2xy+3y+2x^2=0. First thing I do is solve for y. So I get y=-2x^2/(2x+3) - fine.
Then I do implicit differentiation on the calculator and I get the correct answer -2(2x+y)/(2x+3), but then I try using the | y to use the value of y found in previous question to give me an answer ONLY in X. I get the error message Constraint expression invalid. impDif(2x*y+3y+2x^2=0,x,y)|y - just won't work.
If I just hit y and enter. I get just y. Not y=-2x^2/(2x+3) like I expect/want. I have found no way to do that. Can you help?

Thank you for any help you can give me.