Answer
$-x-y=1$
Work Step by Step
The result of exercise 32 tells us that ${\bf v}=\langle a,\ b \rangle$ is parallel to the lines $bx-ay=c$.
Here, ${\bf v}=\langle 1,\ -1 \rangle$ and the lines are $-x-y=c.$
Since $P(-2,1)$ is on the line, its coordinates satisfy the line equation
$\left\{\begin{array}{l}
-(-2)-(1)=c\\
c=1
\end{array}\right.$
So the line equation is: $\quad -x-y=1$
To graph the line, use the given point and $(-1,0)$.
