# Parallel and perpendicular lines?

• Jul 10th 2011, 12:59 PM
homeylova223
Parallel and perpendicular lines?
Write an equation of the line through the point that is parallel to the given line and perpendicular.

Point (7/8,3/4) line 5x+3y=0

which I turned into y=-5/3x

Then I plug into

(y-3/4)= -5/3(x-7/8) This is for parallel

3(3/4)=-5(x-7/8) Did I set this up correct

My second question is

(2,5) x=4 how would I set it up if the slope is undefined?(Headbang)
• Jul 10th 2011, 01:07 PM
Plato
Re: Parallel and perpendicular lines?
Quote:

Originally Posted by homeylova223
Write an equation of the line through the point that is parallel to the given line and perpendicular.
(2,5) x=4

Given the line $x=4$ and point $(2,5)$
one answer is $y=5$ and the other is $x=2$.
Which is which?
• Jul 10th 2011, 01:11 PM
homeylova223
Re: Parallel and perpendicular lines?
Hmm I guess x=2 would be the parallel and y=5 perpendicular
• Jul 10th 2011, 01:13 PM
Plato
Re: Parallel and perpendicular lines?
Quote:

Originally Posted by homeylova223
Hmm I guess x=2 would be the parallel and y=5 perpendicular

Correct.
• Jul 10th 2011, 04:27 PM
homeylova223
Re: Parallel and perpendicular lines?
Would this be parallel for my first question

3(y-3/4)=-5(x-7/8)

3y-2.25=-5x+4.375
3y=-5x+6.625

y=-5/3x+6.625/3 ?
• Jul 10th 2011, 04:38 PM
mr fantastic
Re: Parallel and perpendicular lines?
Quote:

Originally Posted by homeylova223
Write an equation of the line through the point that is parallel to the given line and perpendicular.

Point (7/8,3/4) line 5x+3y=0

which I turned into y=-5/3x

Then I plug into

(y-3/4)= -5/3(x-7/8) This is for parallel

3(3/4)=-5(x-7/8) Did I set this up correct

[snip]

Yes.