### Home > PC > Chapter 12 > Lesson 12.1.2 > Problem12-20

12-20.

Let $M = \left[ \begin{array} { c c } { 1 } & { - 2 } \\ { 2 } & { 0 } \\ { - 1 } & { 3 } \end{array} \right]$, $p =\langle 1,2,3 \rangle$, and $q = \langle 10,20,30 \rangle$. Given that $pM = \langle 2,7 \rangle$, find $qM$. (You should be able to do this without computing.)

If $q = 10p$, then $qM = 10pM$.