Question

Math: https://snipboard.io/DYXpjn.jpg

Answer 1

\[proj _{u}v=\frac{ u.v }{ \left| v \right|^{2} }v\]
\[u.v=\left(\begin{matrix}-12 \\ -5\end{matrix}\right).\left(\begin{matrix}3 \\ 9\end{matrix}\right)\]=-36-45=-81
\[\left| v \right|^{2}=9+81=90\]
\[proj _{u}v=\frac{ -81 }{ 90}v=\left(\begin{matrix}\frac{ -27 }{ 10 } \\ \frac{ -81 }{ 10 }\end{matrix}\right)\]

Answer 2

Okay thank you for the great explanation is option A is the correct answer!