CPM Homework Help : PC3 Problem 8-106

Given $\vec { \text{m} } = \langle - 7 , - 1 \rangle$ and $\vec { \text{n} } = \langle 5,2 \rangle$ , calculate $\arg\left(\vec{\text{p}}\right)$ and $|| \vec { \text{p} } | |$ where $\vec { \text{p} } = 6 \vec { \text{m} } - 8 \vec { \text{n} }$ .

Hint:

Use the Pythagorean Theorem to determine the length of vector $\text{p}$ .
$\arg\left(\vec{\text{p}}\right)$ is the direction. Be sure to consider which quadrant the vector is in when giving your final answer.