Parallel lines (same slopes)
y = mx + b
y = mx + c
For example:
y = 3x + 2
y = 3x + 5
Perpendicular lines (slopes are negative reciprocals)
y = mx + b
y = (-1/m)x + c
For example:
y = 3x + 2
y = (-1/3)x + 4
2007-12-24 08:21:52
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answer #1
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answered by Puzzling 7
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For two parallel lines, coefficients of x and y are the same, the constant may or may not be the same.
eg
2x+3y=4
2x+3y=9
For the equation of a line perpendicular to another line, interchange coefficients of x and y and negate the coeffitcient of y after interchanging, and introduce some constant.
eg:
for 2x-3y=6, perpendicular line is of the form,
-3x-2y=k
value of k can be found by substituting any point like (1,2) that lies on the perpendicular line.
:)
2007-12-24 08:26:56
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answer #2
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answered by ♣♠The Boss♠♣ 3
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2 equations w/ a parallel lines will ALWAYS have the same slope
2 equations w/ perpendicular lines will ALWAYS have slopes, when multiplied, will be the negative reciprocal
e.g. y = -4x - 5 and y = -4x+8
the slope (m) is -4
the slopes are the same
the lines are parallel
e.g. y = -4x - 5 and y = 1/4x +8
the slope (m) is -4 x -1= 4 and find the reciprocal
which is 1/4
2007-12-24 08:23:16
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answer #3
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answered by kd3223 2
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The equation for a line has the form of:
y=mx + b
if two lines are parallel, then the m terms for both lines will be identical, but the b terms will be different.
so the following lines are parallel,
y =3 x + 4
y= 3x - 4
y= 3x
2007-12-24 08:24:13
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answer #4
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answered by WhatWasThatNameAgain? 5
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parallel line equations have the same slope such as y=3x+2 and y=3x-9
Perpendicular lines have slopes that are the inverse and opposite signs such as y=4x+2 and y=-1/4x+10
2007-12-24 08:24:09
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answer #5
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answered by Sarah L 2
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for parallel, write an equation then place || inbetween
for perp, place a + inbetween
2007-12-24 08:21:37
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answer #6
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answered by csd 3
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