Find the cross product vec$(u)$vec$(v)$ where

vec$(u)=3i-4j+9k$ and vec$(v)=($:$7,-5,6$:$).$

$($Enter your answer as $.)$

vec$(u)$vec$(v)=$

please provide as much detail as possible. many thanks. please show how to use the formula and the matrix. i realy need help with the matrix