consider the line y=-7/8x+8

Question

Find the equation of the line that is perpendicular to this line and passes through the point
 −7, 3


Find the equation of the line that is parallel to this line and passes through the point
 −7, 3

Answer 1

y= (-7/8)x+8

 

Line perpendicular will have negative reciprocal slope= 8/7

passes thru point (-7,3)

y=mx+b

3=(8/7)(-7) +b

3=-8+b

11=b

y=(8/7)x+11

 

Line parallel will have the same slope=-7/8

passes thru point (-7,3)

y=mx+b

3=(-7/8)(-7)+b

3=49/8+b

3-49/8=b

-25/8=b

y=(-7/8)x-25/8

Answer 2

y=(-7/8)x+8

y=mx+b is the slope-intercept form of the equation

perpendicular lines have slopes that are negative reciprocals of each other

y=(8/7)x+b, point (-7,3)

3=(8/7)(-7)+b

3=-8+b

3+8=b

11=b

y=(8/7)x+11  answer

 

y=(-7/8)x+8

parallel lines have the same slope

y=(-7/8)x+b, point (-7,3)

3=(-7/8)(-7)+b

3=(49/8)+b

3-(49/8)=b

3-6 1/8=b

-3 1/8=b

(-25/8)=b

y=(-7/8)x-(25/8)  answer