SOLUTION: How do I find the equation of a line parallel/perpendicular without a point that it goes through? example: y=3x+9 (I don't have a point that it goes through) do i just plug i

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Question 135170: How do I find the equation of a line parallel/perpendicular without a point that it goes through?
example: y=3x+9 (I don't have a point that it goes through)
do i just plug in zero for x and solve, then plug zero for y and solve?
Found 2 solutions by stanbon, josmiceli:
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
find the equation of a line parallel/perpendicular without a point that it goes through?
example: y=3x+9 (I don't have a point that it goes through)
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The given line has a slope of 3
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"ANY" line parallel to the given line must have slope = 3. e.g. y = 3x+k
where k is any number.
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"ANY" line perpendicular to the given line must have slope = -1/3.
e.g. y (-1/3)x + k where k is any number
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Cheers,
Stan H.

Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website!
All you know in this case is the slope of a parallel or perpendicular
line. If the equation is , then a parallel line
will have slope = .
A perpendicular line will have slope = . You can write general
equations in which the y-intercept is unknown like this:
for a parallel line
for a perpendicular line
In the parallel case, shouldn't be , since that would
make it the same line as the original.