Solution: Vectors

The cross product of 3-component vectors is defined as:

a = <a1, a2, a3>
b = <b1, b2, b3>
a x b = <a2b3 - a3b2, a3b1 - a1b3, a1b2 - a2b1>

v x w = <9-10, 30-12, 8-18> = <-1, 18, -10>

Answer: <-1, 18, -10>