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Math Help - Soling Equations

  1. #1
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    Soling Equations

    Would appreciate any help with the following question as I do not know where to start.

    7, -2, 5, 3, 8

    In the sequence above, each term after the first two terms is the sum of the previous two terms.

    For example: 3rd term = 5 = 7 +(-2)

    (a) A sequence follows the above rule.

    The first term is x and the second term is y

    The fifth term is 5.

    X, y, -, -, 5

    Show that 2x+3y=5


    (b) Using the same x and y, another sequence follows the above rule.

    The first term is y and the second term is x.

    The sixth term is 17.

    Y, x, -, -, -, 17.

    Write down another equation in x and y.


    Find the values of x and y.
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  2. #2
    MHF Contributor
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    Hi

    The first term is x and the second term is y
    Therefore the third term is x+y [1st+2nd], and the fourth is y+(x+y) [2nd+3rd]
    What is the 5th term ?
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  3. #3
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    Sorry eunning-gag but I'm still stuck
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  4. #4
    MHF Contributor
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    1st term = x
    2nd term = y

    Each term after the first two terms is the sum of the previous two terms
    Therefore
    3rd term = 1st term + 2nd term = x+y
    4th term = 2nd term + 3rd term = y + (x+y) = x + 2y
    5th term = 3rd term + 4th term = (x+y) + (x+2y) = 2x + 3y
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