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Intersections homework help

  1. Sep 27, 2004 #1
    how wud i do the following:

    1.ax+by=c, y=2ax
    2.y=mx+c, y=-mx+d
    3.ax-by=1, y=x
    4.some values for a,b and c for which equation does not represent a straight line, give egs

    ive dun simpler versions of 1-3 but i haven't come across the above, so cud someone please tell me a simple method of working them out. thanks
  2. jcsd
  3. Sep 27, 2004 #2


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    Staff Emeritus
    Science Advisor
    Gold Member

    In general, plug one equation into the other to eliminate x or y from one equation. Solve for the remaining variable, take that solution and use it to determine the other variable.

    These are pretty straight forward problems, give it a bit of thought and play with what I said above.

    BTW: This should be posted in the homework forum.
  4. Sep 27, 2004 #3
    i did post the same thing in the homework section but i didnt get a reply which i needed quite badly, so i came here instead. btw. i still dont understand how to do these particular questions, i have used tht method for slightly simpler questions, but this question just puzzles me
  5. Sep 27, 2004 #4
    How long did you wait for a reply? Don't forget that everybody here has different schedules than what you do.
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