The equation of the line is
.
Let the slope of the line be
.
Compare the equation of the line with the slope-intercept form
.
Where m = slope of the line and b = y-intercept.
\Therefore
.
Let the slope of another line be
.
If the two nonvertical lines are parallel, then their slopes are equal. That is
.
Therefore slope of the line parallel to the line
is also 8.
If the two nonvertical lines are perpendicular, then their slopes are negative reciprocals of each other. That is
.
Therefore slope of the line perpendicular to the line
is
.
The slope of a parallel line is 8 and the slope of a perpendicular line is
.