I need help answering this question.

"Use vectors v=2i+3j-k and z+-3i-j-4k to prove that -(v X z) = z X v. Write a summary and show graphically what this means with respect to the cross product v X z."I get 13i + 11j + 7k as the cross product of both -(v X z) and z X v so I understand how to prove this algebraically, but I have no idea how i would write a summary about this or show this graphically.

Help is greatly appreciated.