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Equation of a line problem

  • Thread starter ruby_duby
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  • #1
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equation of a line problem!!!

The points A and B have co-ordinates (3,4) and (7,-6) respectively. the straight line S passes through A and is perpendicular to AB.
FInd an equation for S, giving your answer in the form ax+by+c=0

Ok so im really stuck on this question. So far i have calculated the gradient of the line AB by doing (-6-4)/(7-3) and i got -2.5

But now i dont know what to do please help :rolleyes:
 

Answers and Replies

  • #2
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How are the slopes of perpendicular lines related?
 
  • #3
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i have no idea how the slopes are related
 
  • #4
cristo
Staff Emeritus
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Two lines with gradients m and m' are perpendicular if (m)(m')=-1
 
  • #5
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so would that mean that my gradient is +2.5
 
  • #6
2,063
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Would it?

If m' x (-2.5) = -1, what does m' = ?
 

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