Question

Find the volume of the box with the vectors A = 2i + j + k , B = 3i - 4j+ 2k , C = i - j+ 2k as edges.

Answer 1

That is just A•B×C

Answer 2

You would want
| A dot (B x C) |
= | <2,1,1> dot <-6,-4,1> | ......... I assume you know how to find cross and dot products
= | -12 - 4 + 1 | = 15 units^3