SOLUTION: Determine which two equations represent perpendicular lines. a)y=4/9x-3 b)y=3x-4/9 c)y=-1/3x+4/9 d)y=1/3x-4/9 Can someone please help me out? Jess

Algebra ->  Algebra  -> Numeric Fractions Calculators, Lesson and Practice -> SOLUTION: Determine which two equations represent perpendicular lines. a)y=4/9x-3 b)y=3x-4/9 c)y=-1/3x+4/9 d)y=1/3x-4/9 Can someone please help me out? Jess      Log On

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Question 148188: Determine which two equations represent perpendicular lines.
a)y=4/9x-3
b)y=3x-4/9
c)y=-1/3x+4/9
d)y=1/3x-4/9
Can someone please help me out?
Jess
Answer by mangopeeler07(462) About Me  (Show Source):
You can put this solution on YOUR website!
answer: b and c
b)y=3x-4/9
c)y=-1/3x+4/9

Why? because their slopes are negative reciprocals of each other.

Slopes-- 3x and -1/3x.

3x reciprocal: 1/3x
negative: -1/3x

-1/3x reciprocal: -3x
negative: 3x

If the slopes are negative reciprocals of each other, then the lines are perpendicular. Always.