True/False question

Suppose that A is a 2 x 3 matrix such that A[1, 1, 1]^t = [2, 3]^t = A[2, 3, 4]^t. Then [1, 2, 3]^t belongs to the nullspace of A.

I have no idea how to start this question/what it means.

1 answer

First, be sure you understand a matrix null space. Google is your friend.

Te null space is all vectors x such that

xA = 0

I'm having a hard time understanding

A[1, 1, 1]^t = [2, 3]^t = A[2, 3, 4]^t

How can they all be equal?