In trial and error method (SIMPLE EQUATIONS) is it compulsory to try and then find the answer or we can find the answer in the first try?

Trial and error is a fundamental method of problem-solving. It is characterized by repeated, varied attempts which are continued until success, or until the practicer stops trying.

If we get the correct answer in the first try we do not need to try further. We can make an educated guess to get the correct answer in the first few trials.