I'm studying for a test and I came across this question: Let $a_1, a_2, . . . a_m \in \Bbb R^n$ such that $m > n+1$. Assume that for the set of m inequalities $a_i^t x ≤ b_i$ there is no feasible solution. Prove that there are $n + 1$ inequalities out of the $m$ which are not feasible.