Answer
$- 21i -33j +18k$
Work Step by Step
Let us consider two vectors $v=xi+yj+zk$ and $w=pi+qj+rk$. Then the cross product of the two vectors $v$ and $w$ can be computed in the form of the determinant as:
$ v \times w=\begin{vmatrix}
i & j & k \\
x & y & z \\
p & q & r \\ \end{vmatrix}$
We have:
$det =-3v \times w =[(-9)(3)-(-6)(1)] i -j [(9)(3) - (-6)(1)]+k [(9)(1) -(-3) (-6)]=- 21i -33j +18k$
