When I drain the bathtub my toilet bubbles and then the tub will drain very slowly. During the time the tub is draining the toilet will not flush. Please Help.

When I drain the bathtub my toliet bubbles and then the tub will drain very slowy. During the time the tub is draining the toliet will not flush. Please Help.
You have a partial blockage in the drain line. The solution would be to snake the line from 1) the lavatory roof vent. 2) pull the toilet and snake from the open closet bend or 3) remove the trip lever plate and snake from the tub waste and overflow. Good luck, Tom