The answer to 'how to unclog bathtub' is to first try using a plunger or a plumber's snake tool to dislodge the clog. If that doesn't work, you can try using a baking soda and vinegar mixture or a chemical drain cleaner. However, it's important to be cautious when using chemical drain cleaners and to follow the instructions carefully.
If the clog persists or you're not comfortable trying to unclog the drain yourself, it's best to call a professional plumber. They have the tools and expertise to safely and effectively clear the blockage without causing any damage to your plumbing system.