finding unknown vertices of triangle from line equations

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Motherof8
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Joined: Sat Feb 12, 2011 12:32 am
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finding unknown vertices of triangle from line equations

The problem states: Lines y = 3 + 2/3x, y =-1/3x, and y = -4/3x +3 intersect to form a triangle. Find the verticies. I solved for x by substituting x for y, then I solved for y and started to plot the lines on a graph. I get a constant value for x, and different values for y, which doesn't form a triangle. Did I do the wrong thing?

maggiemagnet
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Joined: Mon Dec 08, 2008 12:32 am
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Re: finding unknown vertices of triangle from line equations

The problem states: Lines y = 3 + 2/3x, y =-1/3x, and y = -4/3x +3 intersect to form a triangle. Find the verticies. I solved for x by substituting x for y, then I solved for y and started to plot the lines on a graph. I get a constant value for x, and different values for y, which doesn't form a triangle. Did I do the wrong thing?
Without seeing what you got or how, it's hard to say. But you might want to start with the fact that the corners of the triangle are where pairs of lines cross. So pick a pair of lines and find the intersection for that pair. That's one corner. Then do a different pair. Then do the last pair. You should get three points. Each one is the "solution" to a "system" that you made up by pairing lines, and each is also a corner point of the triangle.

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