Let A be some matrix with entries in . Prove the following:

a) A system of equations with Ax=0 with m<n has a non-trivial solution.

Firstly does a non-trivial solution (in this case) mean a solution where ?

As for working out the question all I can think of is that if m<n, then there are more equations than there are variables, with the variables being . But I can't quite see how this would give a non-zero solution.