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Math Help - Simultaneous Equations, Non Linear Equations and Equations with 3 unknown pronumerals

  1. #1
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    Simultaneous Equations, Non Linear Equations and Equations with 3 unknown pronumerals

    I have these exercises for homework but I dont understand them, I have read the examples but I can't comprehend how the examples work.

    If you know how to do these could you please explain them in simple terms. I am stressing out over this please help
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  2. #2
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    Quote Originally Posted by Needhelpatmaths View Post
    I have these exercises for homework but I dont understand them, I have read the examples but I can't comprehend how the examples work.

    If you know how to do these could you please explain them in simple terms. I am stressing out over this please help
    If you expect to get help you will need to post the actual questions.
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  3. #3
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    Right

    Ok I will provide a sample questionof each:

    Simultaneous Equations:

    3a + 2b = 5 and 2a - b = -6


    Non Linear Equations:

    xy = 6 and x + y = 5


    Equations with 3 Unknown Variables:

    a - b + c = 7 , a + 2b - c = -4 and 3a - b - c = 3
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  4. #4
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    Quote Originally Posted by Needhelpatmaths View Post
    Ok I will provide a sample questionof each:

    Simultaneous Equations:

    3a + 2b = 5 and 2a - b = -6

    Mr F says:

    3a + 2b = 5 .... (1)
    2a - b = -6 .... (2)

    Multiply equation (2) by 2 and add it to equation (1): 7a = -7 => a = -1.

    Substitute a = -1 into either equation and solve for b.


    Non Linear Equations:

    xy = 6 and x + y = 5

    Mr F says:

    xy = 6 .... (1)
    x + y = 5 => y = 5 - x .... (2)

    Substitute equation (2) into equation (1):

    x(5 - x) = 6 => 5x - x^2 = 6 => x^2 - 5x + 6 = 0.
    Therefore x = 2, 3.

    Substitute the values of x into equation (2) and solve for y.


    Equations with 3 Unknown Variables:

    a - b + c = 7 , a + 2b - c = -4 and 3a - b - c = 3

    Mr F says:

    a - b + c = 7 => c = 7 - a + b.... (1)
    a + 2b - c = -4 .... (2)
    3a - b - c = 3 .... (3)

    Substitute equation (1) into equations (2) and (3) and simplify:

    2a + b = 3 .... (A)
    2a - b = 5 .... (B)

    Add equations (A) and (B) together: 4a = 8 therefore a = 2.

    Substitute a = 2 into equation (A) or (B) and solve for b. Then substitute the values of a and b into equation (1) and solve for c.
    ..
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