Hello, we were given a few practice problems in class the other day and one of them asks...

Simplify a x [a x (a x b)] dot c (where the x refers to cross product)

I have tried to simplify it but have ended up with about a page and a half of computation that I don't know what to do with.

I imagine there is a trick to this but I am clueless. If anyone can help I would appreciate it.