If you arrived at the correct answer, you should have received more than 1/4 points.

If you are failing the class, you need to bring it up with the head of the department/principal/ whoever is that teacher's boss.

If you are not in danger, you are better off just accepting the method taught in class and using that and letting it go.

After you learn the method taught by your instructor, prove to him that you arrive at the same answer every time using your own method and step by step evidence that you are correct.

Or at least prove it to yourself anyway, most teachers I have known don't like it when students are smarter than they are and in high school it is usually the case, since teaching colleges are some of the most relaxed and easy there are, at least in my area. (College is a totally different matter, so don't get used to it.)