



 
Hanbal, What a strange problem. I wonder if you have written it down correctly. THE EQUATION OF AC IS IRRELEVANT! You just have to find the slope of AD, which is the line joining A to D. The slope of the line DC (that you seek) is then the negative of the reciprocal of the slope of AD. (This means that if you found the slope of AD to be p/q, then the slope of DC is q/p.) The desired line DC has an equation with slope q/p that is satisfied by (x, y) = (5, 5). Chris  


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