Cross Product of Two Vectors: Finding Component Along Direction of C

[Midas_Touch]

I have two vectors A = 2x + 3y - 4z and B = -6x - 4y + z. The problem asks me to find the component of A X B along the direction of C = x - y + z. So I did put A and B into a matrix, but I didn't get the correct answer, which is -14.4. What am I doing wrong?

 

[mezarashi]

First, find the vector D = A X B.
Then find the unit vector in the C direction.
Finally dot D with the unit vector of C.

 

[Midas_Touch]

First, find the vector D = A X B.
Then find the unit vector in the C direction.
Finally dot D with the unit vector of C.

I got -15 instead of -14.4 (the answer from the back of the book). I am not sure why it's a little off.

 

[mezarashi]

I can only suggest an algebriac mistake.