The equation in the problem is in slope-intercept form. The slope-intercept form of a linear equation is:
y
=
m
x
+
b
Where
m
is the slope and
b
is the y-intercept value.
y
=
3
x
+
7
has a slope of:
m
=
3
Let's call the slope of a perpendicular line
m
p
The formula for
m
p
is:
m
p
=
−
1
m
Substituting gives:
m
p
=
−
1
3
