See HOW it is gurgling - is the water in the toilet being pulled down into the toilet outlet opening, followed by gurgling as air passes from the pipe into the bottom of the toilet once the water in the toilet trap (the bottom of the bowl) has been pulled out - which would mean after the gurgling is over, the water level in the toilet bowl would be unusually low ? If that is the case, almost certainly a blocked vent pipe (the line that goes through the roof to vent outside), so replacement air is not coming into the sewer line to prevent a prtial vacuum as the draining water flows down the line.
If air bubbles are coming UP into the toilet but the water level is not being drawn down significantly, then most likely you have a partial blockage in the line downflow of the toilet and tub, and as the tub (or washer) is draining the water is filling the pipe up (because the water is backing up in the pipe due to the partial blockage) which is causing the air in the pipes to back up into the toilets as the pipe fills with water. Eventually, as the blockage becomes more complete (which might takes weeks or might occur at the next flushing of solids), this will likely transition into a backup of water into the lower level drains, or a near total refusal of the lowest elevation drain in the house to drain at all. Usually, as it gets worse, you will find during high volume ewater discharge that the water/sewage sstarts coming up form the lowest elevation drain on the plugged line.
If the blockage is in the household piping, then the backup would occur at the lowest elevation drain upstream of the blockage, or sometimes gurgling at several drains. If the main sewer line to street or septic system is what is blocked (the usual case, bacause it is much flatter slope in general) then the gurgling and then backup would normally be at the lowest elevation drain in the house - commonly a basement shower/tub or floor drain if you have one.
Because you have gurgling both from washer (usual first cause because of highest outflow rate and high volume) and from tub, the blockage (assuming this is due to a backup rather than vent stack blockage) would be downstream of all those fixtures, if you can trace your piping.
You can find a number of previous similar questions about drain noise and partial backups in the Home > Plumbing link under Browse Projects, at lower left - a couple of those are provided below as a starter:
Contractor to remedy this issue - if you know it is in-house, a Plumber can commonly handle it. If in the lines to the sewer/septic tank, some plumbing companies have the long-reach equipment to clear blockages there, but Sewer and Drain (or is it Drain and Sewer ?) Cleaning outfits are the ones to normally handle this. My recommendation - if in underground line, have the entire thing routed/jetted out to the septic tank or street, because just punching through the blockage does not always clear it completely, plus it can break up and move downflow and plug up again, resulting in a repeat situation in hours to days commonly - so unless your line has been thoroughly routed out inthe past 5-7 years, I recommend full-diameter cleaning to the outlet - something that should normally be done every 10-20 years anyway, depending on whether you dump grease or a lot of garbage disposal grindings down the drain (which is bad) and how much quite hot water is dumped down the drains in normal use (dishwasher and clothes washer are most effective), which is a good thing for drains.