Question

Your mother asked you how you doing how to respond in French?

Answer 1

  je vais bien= im doing fine
  l'echol est formidable=school is great

Answer 2

Hello!

The common way to ask "How are you?" In French is "Comment ça va?"

A couple of appropriate answers include:
Good - Bien
Very good - Très bien

If your mother asks you "Comment ça va?" You can simply answer with either of the above options. If you want to add "and you?" You would add "Et toi?"

An appropriate answer to the question may be "Bien! Et toi?" Which means "Good! And you?"

I hope this helps you! Have a great day!