Question

Mes parents et moi ________ du tennis tous les samedis.

Answer 1

Answer these simple questions:
1st: which verb is to be used?
2nd: what person is needed?

Answer 2

I think it should be ; font

Answer 3

Correct verb, but wrong person :)

Answer 4

It should be faisons because the person (or part of speech) should be in the nous. Whenever you are dealing with someone + moi or I, it should be in the nous. Nous means "we" and the correct conjugation should be faisons ("faire du tennis" is the infinitive). The "font" is in the ils/elles or the "they" form and it wouldn't make sense considering the context.