SOLUTION: determine which two equations represent perpendicular lines A. y= 4/7x-3 B. y=3x-4/7 C. y= -1/3x+4/7 D. y= 1/3x-4/7 i am completely confused

Algebra ->  Graphs -> SOLUTION: determine which two equations represent perpendicular lines A. y= 4/7x-3 B. y=3x-4/7 C. y= -1/3x+4/7 D. y= 1/3x-4/7 i am completely confused      Log On


   

Question 121922: determine which two equations represent perpendicular lines
A. y= 4/7x-3
B. y=3x-4/7
C. y= -1/3x+4/7
D. y= 1/3x-4/7
i am completely confused
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Perpendicular lines have slopes that are negative reciprocals of each other.
In other words,
m%5B1%5D%2Am%5B2%5D=-1
The product of the slopes is -1.
All of your equations are in slope-intercept form.
y=mx%2Bb
and
m%5B1%5D=4%2F7
m%5B2%5D=3
m%5B3%5D=-%281%2F3%29
m%5B4%5D=1%2F3
From your 4 choices, the answer is B and C since
3%2A%28-1%2F3%29=-1
Graphing the equations, you see they are perpendicular.
+graph%28+300%2C+300%2C+-5%2C+5%2C+-5%2C+5%2C+3x-4%2F7+%0D%0A%2C+-%281%2F3%29x%2B4%2F7+%29+