write the equation of the line that is perpendicular to the graph of y=3/4x-3, and whose y-intercept is -8
step 1
Find the slope of the given line
y=(3/4)x-3
the slope is m=3/4
step 2
Find the slope of the perpendicular line
REmember that
If two lines are perpendicular, then the product of their slopes is equal to -1 (inverse reciprocal)
so
the slope of the perpendicular line is
m=-4/3
step 3
Find the equation of the line
we have
m=-4/3
y-intercept is -8
so
b=-8
y=mx+b
substitute
y=-(4/3)x-8
Part 2
write an equation of the line that is parallel to the graph of y=-4x-9, and whose y-intercept is 3
step 1
Find the slope of the given line
y=-4x-9
the lope is m=-4
step 2
Find the slope of the parallel line
Remember that
If two lines are parallel, then their slopes are the same
so
the slope of the parallel line is m=-4
step 3
Find the equation of the line in slope intercept form
y=mx+b
we ahve
m=-4
b=3
substitute
y=-4x+3