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 Please instruct me on how to do this

Algebra ->  Linear-equations -> 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 Please instruct me on how to do this      Log On


   

Question 68476: 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
Please instruct me on how to do this
Found 2 solutions by funmath, rmromero:
Answer by funmath(2933) About Me  (Show Source):
You can put this solution on YOUR website!
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
Perpendicular lines have slopes that are negative reciprocals of each other. (That means that they have opposite signs and are upside down.)
When equations are in slope intercept form: highlight%28y=mx%2Bb%29, we know that the slope is m.
A y=highlight%284%2F7%29x-3 m=4/7
B y=highlight%283%29x-4%2F7 m=3
C y=highlight%28-1%2F3%29x%2B4%2F7 m=-1/3
D y=highlight%281%2F3%29x-4%2F7 m=1/3
B and C have slopes that are opposite signs and reciprocals of each other, so they are perpendicular.
Happy Calculating!!!

Answer by rmromero(383) About Me  (Show Source):
You can put this solution on YOUR website!
A y= 4/7x-3 B y= 3x-4/7 C y=-1/3x+4/7 D y= 1/3x-4/7
To determine which two equations are perpendicular, You can graph all the equation. If you have two nonvertical lines that are perpendicular, the slopes are the negative reciprocal of the orignal slope.


B.) y+=+3x+-+4%2F7, m = 3

C.) y+=%28-1%2F3%29x+%2B+4%2F7, m = -1/3
3 is the negative reciprocal of -1/3.
Therefore, Answer is B and C

Look at the graph.

graph+%28200%2C+200%2C+-8%2C+5%2C+-8%2C+5%2C+3x-4%2F7%2C+%28-1%2F3%29x%2B4%2F7%29

Here's the graph of the rest of the two equations
graph+%28200%2C+200%2C+-8%2C+5%2C+-8%2C+5%2C+%284%2F7%29x-3%2C+%281%2F3%29x-4%2F7%29

The red line shows the graph y= 4/7x-3.
The green line shows y= 1/3x-4/7