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Consider the line y=9x-3.Find the equation of the line that is perpendicular to this line and passes through the point (-8, – 5).Find the equation of the line that is parallel to this line and passes through the point (-8, -5).

User Ibrahimyilmaz
by
2.6k points

1 Answer

17 votes
17 votes

step 1

Find the slope of the given line

y=9x-3

the slope is m=9

step 2

Remember that

If two lines are perpendicular, then their slopes are negative reciprocal

that means

the slope of the perpendicular line is

m=-1/9

step 3

Find the equation of the line that is perpendicular to this line and passes through the point (-8, – 5).

we have

m=-1/9

point (-8,-5)

the equation in slope-intercept form

y=mx+b

substitute and solve for b

-5=(1/9)(-8)+b

-5=-(8/9)+b

b=-5+8/9

b=-37/9

y=-(1/9)x-37/9

step 4

Find the equation of the line that is parallel to this line and passes through the point (-8, -5).

Remember that

If two lines are parallel, then their slopes are equal

the slope of the parallel line is

m=9

the equation in slope-intercept form

y=mx+b

substitute and solve for b

-5=9(-8)+b

-5=-72+b

b=67

therefore

y=9x+67

User Phil Gyford
by
3.3k points