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anonymous

  • 5 years ago

Solve by graphing. If there isn't a unique solution to the system, state the reason. x-y=3 x+y=5 Please explain how to solve. I was only able to find one point which I understand is the answer but how do I find the other points to determine where my lines are on the graph?

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  1. anonymous
    • 5 years ago
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    Well two lines intersect at 1 point, infinite points(they are the same), or don't intersect(they are parallel).

  2. anonymous
    • 5 years ago
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    The point you find is probably the right point.

  3. anonymous
    • 5 years ago
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    (4,1)

  4. anonymous
    • 5 years ago
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    You should graph each line separately, be putting it in standard form if you like y = mx + b. and put in the intercepts and what not

  5. anonymous
    • 5 years ago
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    But I need to know how to get the rest of the points to figure out what type of lines I have. ex: consistent, dependent, inconsistent

  6. anonymous
    • 5 years ago
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    What do you mean by that? Two lines in a plane, will only intersect at most one point. Or they will be the same line. Or if they are parallel they will never intersect.

  7. anonymous
    • 5 years ago
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    To graph it, you can take the first line and make it y = x - 3. Find the intercepts: by setting y = 0, solving for x. Then set x=0, solving for y. Plot these points and draw a line between them. That will be your first line.

  8. anonymous
    • 5 years ago
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    Ok I have the point on the graph. Which way do you draw the line? I can draw the line in many directions. How do I find point 2 to give me the direction of my line?

  9. anonymous
    • 5 years ago
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    (4,1) is my first point after solving for X and Y

  10. anonymous
    • 5 years ago
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    So we will take the first line x - y = 3. Set y=0 and find that x = 3. | |<---- y=3 when x = 0 -------- <---- x=3 when y= 0 | |

  11. anonymous
    • 5 years ago
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    You can do the same with the second line.

  12. anonymous
    • 5 years ago
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    WAIT sorry y=-3! so it will be below the x-axis.

  13. anonymous
    • 5 years ago
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    I hate to seem like an idiot but how did you get the -3 exactly?

  14. anonymous
    • 5 years ago
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    I solved the equation like this: x-y=3 x+y=5 add both equations 2x=8 Y's cancel and then divide both sides by 2 x=4 Then I did the same thing only cancelling the X's and then solved for Y getting Y=1

  15. anonymous
    • 5 years ago
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    This gave me the intersecting point. Now I need to find the other points to know which way my two lines are going.

  16. anonymous
    • 5 years ago
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    a

  17. anonymous
    • 5 years ago
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    Ha don't say that. I am probably explaining badly

  18. anonymous
    • 5 years ago
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    You did that perfectly. We can now just draw the lines. We can get -y =3 because x - y =3; x=0 (0) -y =3.

  19. anonymous
    • 5 years ago
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    so the first line will go through (0,-3) (3,0) and (4,1)

  20. anonymous
    • 5 years ago
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    ok I understand now. Thanks for your help. I just got a little stuck.

  21. anonymous
    • 5 years ago
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    No problem!

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