Question

Let u = <-5, -9>, v = <6, 8>. Find -8u - 2v.

Answer 1

<28, 56>

Explanation:

u = -5i - 9j

v = 6i + 8j

-8u - 2v = 40i + 72j - 12i - 16j = 28i + 56j

-8u - 2v = <28, 56>

Answer 2

`\bf \begin{cases} u=\ \textless \ -5,-9\ \textgreater \ \\ \qquad -8u\\ \qquad -8\ \textless \ -5,-9\ \textgreater \ \\ \qquad \ \textless \ 40,72\ \textgreater \ \\\\ v=\ \textless \ 6,8\ \textgreater \ \\ \qquad 2v\\ \qquad 2\ \textless \ 6,8\ \textgreater \ \\ \qquad \ \textless \ 12,16\ \textgreater \ \end{cases} \\\\\\ -8u-2v\implies \ \textless \ 40,72\ \textgreater \ ~-~\ \textless \ 12,16\ \textgreater \ \\\\\\ \ \textless \ 40-12~~,~~72-16\ \textgreater \ \implies \ \textless \ 26~~,~~56\ \textgreater \`