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

Algebra ->  Points-lines-and-rays -> 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       Log On


   

Question 102748: 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
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Well, by inspection, you can see that the slopes of the lines represented by these four equations are all positive, so there are no perpendicular lines.
Why? Because perpendicular lines have slopes that are the negative reciprocal of each other and, as you can see, there are no negative slopes, ergo, no perpendicular lines.
a) y+=+%284%2F7%29x-3 Compare with: y+=+mx%2Bb Slope m+=+4%2F7
b) y+=+3x-%284%2F7%29 Slope m+=+3
c) y+=+%281%2F3%29x%2B%284%2F7%29 Slope m+=+%281%2F3%29
d) y+=+%281%2F3%29x-%284%2F7%29 Slope m+=+%281%2F3%29
The lines represented by equations c) and d) have equal slopes, so these lines are parallel.