# Math Help - 3D Vector Problem Help

1. ## 3D Vector Problem Help

Problem:

Determine x and y if vectors a=[x, y, 1], b=[1, 2, 3] and a x b=[7, -5, 1].

y=3
x=2

2. Simply multiply it out and solve for each component.

For example, looking at the x-component of a x b:

$\left| \begin{array}{cc} y & 1 \\ 1 & 2 \end{array} \right| = 7$
$2y - 1 = 7$

etc. etc.

3. I don't understand what you mean.

4. Forget it! I figured it out thanks to your clue. Thanks!