Hey everyone

I'm having a little trouble on this homework trying to prove or disprove this problem.

Let A, B, and C be sets. Prove or disprove that A − (B ∩ C) = (A − B) U (A − C).

Hint: difference of two sets, De Morgan’s law, distributive law for intersection over union.

The teacher said the first step to this is:

Step 1: A − (B ∩ C) = A ∩ B ∩ C

But I don't see where he got the A n B n C from anywhere, or where to go after wards, any suggestions?