Question - What is the equation of the line that passes through the point (1,3) and has a slope of -3
Answer/explanation - You only need another point on the line through ,
S
,
and the vector −
Q
−
P
is parallel to the given line through ,.
P
,
Q
.
So another point on the line through
S
parallel is +−.
S
+
Q
−
P
.
Then in the desired form that line is +(+−),
x
S
+
y
(
S
+
Q
−
P
)
,
where +=1.