I have a bad toothache & the wisdom tooth it's decayed and broken which is better to get root canal or extraction? Dentist gave me those 2 options

Extraction. It's very rare to see someone in their later years that have wisdom teeth. They are typically hard to clean and difficult to work on. I would suggest an extraction and not spend the money on it. Unless your dentist has a very specific reason to keep it, I would recommend having it out. Best of luck!
Extraction. Sometimes wisdom teeth are valuable asset when healthy and properly aligned, but more often, they are misaligned and require removal. See your dentist for wisdom tooth removal.
Extraction.. in my opinion, wisdom teeth are so far in the back of your mouth that it is usually extremely difficult to keep those areas disease free (from decay or gum disease). Bacteria therefore accumulate and cause decay and bone loss and can effect the teeth in front of them, your second molars.
Evaluate all 4. Is the opposing tooth there? Have a complete and through treatment plan. Have the dentist evaluate all the wisdom teeth to ascertain whether they are worth saving or extracting. If the opposing tooth is in occlusion, it may warrant saving to avoid extrusion of the opposing tooth.