Question 212889:  determine if lines l1 and l2 are parallel, perperdicular or neither 
l1:y=10/9x-1/7 
l2:y=9/10x-9/10 
 Answer by drj(1380)      (Show Source): 
You can  put this solution on YOUR website! Determine if lines l1 and l2 are parallel, perperdicular or neither
 
l1:y=10/9x-1/7 (slope-intercept form) 
l2:y=9/10x-9/10 (slope-intercept form)
 
 
Step 1.  Line 1 has slope of 10/9 and Line 2 has slope of 9/10 by looking at slope-intercept form of y=mx+b where m is the slope and b is the y-intercept.
 
 
Step 2.  Since the slopes of Line 1 and 2 are not equal they are not parallel.
 
 
Step 3.  Since the product of the two slopes does not equal to -1 they are not perpendicular.  The product is 1 in this case since (10/9)(9/10)=1
 
 
Step 4.  Therefore the lines are neither perpendicular nor parallel.
 
 
I hope the above steps were helpful.
 
 
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Good luck in your studies!
 
 
Respectfully, 
Dr J 
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