Compute all intersections of the following lines:
x-y-1=0, -x-2y-3=0, y-x=0, 2x-2y-1=0
You should have more than three intersections

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Request for Question Clarification by websearcher-ga on 24 Sep 2002 11:44 PDT

Hi eksolutions:

Those lines have *exactly* three intersections. Three of the lines are
parallel to each other and the fourth line crosses each of them -
giving three intersections exactly. Would giving you those three
intersections be sufficient?

Thanks. 

websearcher-ga

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Clarification of Question by eksolutions-ga on 24 Sep 2002 11:50 PDT

Yes, that's all I need...

Hi eksolutions:

As I said earlier, three of these lines are parallel. This can be seen
better if we rewrite them in a different format:

x-y-1=0    ->  y=x-1
y-x=0      ->  y=x
2x-2y-1=0  ->  y=x-1/2

Each of these lines is crossed by -x-2y-3=0. 

-x-2y-3=0 and x-y-1=0 cross at [x=-1/3, y=-4/3]

-x-2y-3=0 and y-x=0 cross at [x=-1, y=-1]

-x-2y-3=0 and 2x-2y-1=0 cross at [x=-2/3, y=-7/6]

This can be seen from the following graph:

http://www.lucidmatrix.com/uploads/intersection.jpg 

Hope this helps! 

websearcher-ga