Question

Consider the line y= -7/4x+8

Find the equation of the line that is perpendicular to this line and passes through the point (-7,-2)

Find the equation of the line that is parallel to this line and passes through the point (-7,-2)

Answer 1

perpendicular line has slope that multiplies to -1
paralel line has same slope

y=mx+b
slope=-7/4
perpendicular
4/7
(-7,-2)
-2=4/7(-7)+b
-2=-4+b
add 4 both sides
2=b
y=4/7x+2


paralel
y=-7/4x+b
-2=-7/4(-7)+b
-2=49/4+b
minus 49/4 from both sides (-2=-8/4)
-57/4=b
y=-7/4x-14.25


perpendicular
y=4/7x+2
paralel
y=-7/4x-14.25