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Math Help - help!!!!

  1. #1
    danielle77
    Guest

    help!!!!

    Hello I'm looking for someone to help explain this to me...


    -7/20x= -21/10

    (4.9-18.6)x 13


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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by danielle77 View Post
    Hello I'm looking for someone to help explain this to me...


    -7/20x= -21/10
    Add brackets to make the intended meaning clear. Is this:

    (-7/20) x = -21/10

    if so multiply both sides by -10/7 to get:

    (-10/7)(-7/20) x = (-10/7)(-21/10)

    which is:

    (1/2)x = 3

    or x=6

    (4.9-18.6)x 13
    This needs to be made clearer, I have no idea what your question is.

    RonL
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  3. #3
    jsebring
    Guest

    multiply by the reciprocals

    your problem, -7/20x=-21/10

    the solution multiply both sides by the reciprocal of -7/20 which is -20/7
    that will isolate x, so your prblem should look like this x=-21/10 x -20/7
    from there you you break the numbers into their prime factorization
    21/10 = 3x7/2x5 and -20/7 = 2x2x5/1x7
    now your numerator should look like this 3x7x2x2x5
    and your denominator should look like this 2x5x1x7 your next step is to multiply 2/2 x 5/5 x 7/7 x 3x2/1 because any number divided by itself is one those first three numbers cancel out and your left with 3x2/1 which equals 6/1 or 6

    hope this helps it should make more since once you write it out
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