Given that the unit vector ABC is perpendicular to each other, simplify (2a-2b + 4C) times (- a-3b + 2C)

Given that the unit vector ABC is perpendicular to each other, simplify (2a-2b + 4C) times (- a-3b + 2C)

(2a-2b + 4C) times (- a-3b + 2C)
=-2a^2+6b^2+8c^2
Because AB, BC, CA are all 0
So there's nothing in the back