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Math Help - need some help with with graphing

  1. #1
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    need some help with with graphing

    I need some help with with graphing liner equations. i am supposed to get 3 order pair solutions then graph it.the thing i am having the most trouble with is geting the 3 order pair aolutions. here are two sample problems. thanks for the help

    x-2y=6

    3y-10=5x
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  2. #2
    MHF Contributor
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    Quote Originally Posted by robpez View Post
    I need some help with with graphing liner equations. i am supposed to get 3 order pair solutions then graph it.the thing i am having the most trouble with is geting the 3 order pair aolutions. here are two sample problems. thanks for the help

    x-2y=6

    3y-10=5x
    An ordered pair here is a point on the graph. Since you have the usual x and y, then an ordered pair is in the form (x,y).
    For every value of x, there is a corresponding value of y, and these two values are the ordered pair on that specific point on the graph.

    Getting ordered pair is easy as pie. You assign a value to, say, x, then you solve for the y.
    Example,
    x -2y = 6
    Say, x=0, so,
    0 -2y = 6
    y = 6/(-2) = -3
    Hence, the ordered pair here is (0,-3).

    You need 3 ordered pairs for this equation. You need two more.

    say, x=2, then,
    2 -2y = 6
    -2y = 6 -2 = 4
    y = 4/(-2) = -2
    Hence, (2,-2) is another ordered pair.

    Last one, say x=4,
    4 -2y = 6
    -2y = 6 -4 = 2
    y = 2/(-2) = -1
    Hence, (4,-1), your 3rd ordered pair.

    Plot those on the same x,y axes, draw a line through them, and you have your graph of the line x -2y = 6.

    Now try the second line.
    Last edited by ticbol; September 21st 2006 at 11:35 PM.
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  3. #3
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    [QUOTE=ticbol;21358]An ordered pair here is a point on the graph. Since you have the usual x and y, then an ordered pair is in the form (x,y).
    For every value of x, there is a corresponding value of y, and these two values are the ordered pair on that specific point on the graph.

    Getting ordered pair is easy as pie. You assign a value to, say, x, then you solve for the y.
    Example,
    x -2y = 6
    Say, x=0, so,
    0 -2y = 6
    y = 6/(-2) = -3
    Hence, the ordered pair here is (0,-3).

    You need 3 ordered pairs for this equation. You need two more.

    say, x=2, then,
    2 -2y = 6
    -2y = 6 -2 = 4
    y = 4/(-2) = -2
    Hence, (2,-2) is another ordered pair.

    Last one, say x=4,
    4 -2y = 6
    -2y = 6 -4 = 2
    y = 2/(-2) = -1
    Hence, (4,-1), your 3rd ordered pair.

    I am still a little confused. in the last problem where did you get the -4
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  4. #4
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    [quote=robpez;21468]
    Quote Originally Posted by ticbol View Post
    An ordered pair here is a point on the graph. Since you have the usual x and y, then an ordered pair is in the form (x,y).
    For every value of x, there is a corresponding value of y, and these two values are the ordered pair on that specific point on the graph.

    Getting ordered pair is easy as pie. You assign a value to, say, x, then you solve for the y.
    Example,
    x -2y = 6
    Say, x=0, so,
    0 -2y = 6
    y = 6/(-2) = -3
    Hence, the ordered pair here is (0,-3).

    You need 3 ordered pairs for this equation. You need two more.

    say, x=2, then,
    2 -2y = 6
    -2y = 6 -2 = 4
    y = 4/(-2) = -2
    Hence, (2,-2) is another ordered pair.

    Last one, say x=4,
    4 -2y = 6
    -2y = 6 -4 = 2
    y = 2/(-2) = -1
    Hence, (4,-1), your 3rd ordered pair.

    I am still a little confused. in the last problem where did you get the -4
    The minus four comes from moving the 4 on the left hand side of:

    4 - 2y = 6

    over to the right hand side.

    You can think of it as subtracting 4 from both sides of the equation:

    (4 - 2y) -4 = (6) -4,

    so:

    4 - 2y -4=-2y=6-4=2,

    which leaves us with:

    -2y=2

    hence:

    y=2/(-2)=-1.

    RonL
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