Answer
$(ca) \times b =c (a \times b)=a(c \times b)$
Work Step by Step
Let $a= a_1i+a_2j+a_3k$ and $b=b_1i+b_2j+b_3k\gt$
$(ca) \times b=\begin{vmatrix} i&j&k \\ ca_1&ca_2&ca_3\\b_1&b_2&b_3\end{vmatrix}$
Using property of determinants,we can write
$= \ c\begin{vmatrix} i&j&k \\ a_1&a_2&a_3\\b_1&b_2&b_3\end{vmatrix}$
Using property of determinants,we can write
$\ c\begin{vmatrix} i&j&k \\ a_1&a_2&a_3\\b_1&b_2&b_3\end{vmatrix}= \ \begin{vmatrix} i&j&k \\ a_1&a_2&a_3\\cb_1&cb_2&cb_3\end{vmatrix}$
$=a(c \times b)$
Hence, $(ca) \times b =c (a \times b)=a(c \times b)$
