Graphs of given pairs

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silverdragon316

Junior Member
Joined
Mar 16, 2007
Messages
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My problem is :

Determine whether the graphs of the given pair of lines are parallel, perpendicular or neither.

x-4y+5...............................................y=1/4x+3
...-4y=-x+5
......y=1/4x-5/4


....slope:1/4..........................................slope:1/4


I would say the answer is parallel since they have the same slope and not perpendicular because their slopes are not reciprocals of each other.

Am I correct?
 
You have three sets you need to identify if they represent a line that would be parallel, perpendicular, or neither.

Code: 
x-4y+5=0
y=1/4x+3

-4y=-x+5
y=1/4x-5/4 

slope:1/4
slope:1/4

Put each of the two first sets of equations in slope-intercept form (y=mx+b)

look at the SLOPE of the line, only.

If the slopes are the same: the lines are parallel
If the slopes are negative inverses (sign change and inverse) than the lines are perpendicular. Example: lines with slope (1/3) and -(3/1) are perpendicular.


Best of luck!
 
silverdragon316 said:
I divided both sides by -4
Click to expand...
Note: It is generally better to reply with corrections, as stealth-edits (going back and changing the initial post) tend only to confuse the conversation (as the replies now no longer make any sense).

Thank you for your consideration.

Eliz.
 
Questions: You need the problem to be in slope form, right?

Also from the second line you are suppose to divide both sides by 4?

Also X has a value of 1, right?
 
You need the problem to be in slope form, right?
Click to expand...
Yes.
Also from the second line you are suppose to divide both sides by 4?
Click to expand...
If you are talking about -4y=-x+5 then you would divide by a -4.
Also X has a value of 1 right?
Click to expand...
x is a variable and has many values. Notice when you solve for x you have y in your answer which is a variable, meaning you don't have a constant answer.
 
Ok, so is my solution correct? That is, the slope of each line is m = 1/4 and the lines are parallel?
 
You are correct! The lines are parallel. Good work solving for y.


Cheers,
John.
 
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