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Math Help - Rational expressions

  1. #1
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    Rational expressions

    Simplifying Rational expressions.

    4x + 4/ 3x-3 X 6x - 6/5x+5

    the question askes to simplify by bringing both terms to lowest common terms before multiplying. The answer is supposed to be 8/5, where 1, -1 are not equal to zero.

    I can't figure out how to obtain my result. Here is my rough work, could someone help me to figure out what I am doing wrong?

    4x + 4/ 3x-3 X 6x - 6/5x+5

    = 4x + 4/ 1-1 X 2-2/5x+5

    =4x + 4/ 0 X 0/5x+5

    = 0/0 = undefined. (we are supposed to "cross-cancel" by crossing out like terms and such)
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  2. #2
    Senior Member OReilly's Avatar
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    Quote Originally Posted by danielle_54321 View Post
    Simplifying Rational expressions.

    4x + 4/ 3x-3 X 6x - 6/5x+5

    the question askes to simplify by bringing both terms to lowest common terms before multiplying. The answer is supposed to be 8/5, where 1, -1 are not equal to zero.

    I can't figure out how to obtain my result. Here is my rough work, could someone help me to figure out what I am doing wrong?

    4x + 4/ 3x-3 X 6x - 6/5x+5

    = 4x + 4/ 1-1 X 2-2/5x+5

    =4x + 4/ 0 X 0/5x+5

    = 0/0 = undefined. (we are supposed to "cross-cancel" by crossing out like terms and such)

    Frenkly I can't figure what is what in 4x + 4/ 3x-3 X 6x - 6/5x+5
    Please use parentheses so we could clearly see what is what.

    And also using x and X... please clarify expression.
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  3. #3
    Senior Member OReilly's Avatar
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    Quote Originally Posted by OReilly View Post
    Frenkly I can't figure what is what in 4x + 4/ 3x-3 X 6x - 6/5x+5
    Please use parentheses so we could clearly see what is what.

    And also using x and X... please clarify expression.

    Well, I have figured out what expression you need to simplify.

    The expression is (if I am right):

    [(4x+4)/(3x-3)] *[(6x-6)/(5x+5)]

    So if I am right then solution is:

    [(4x+4)/(3x-3)] *[(6x-6)/(5x+5)] =
    [(4(x+1))/(3(x-1))] *[(6(x-1))/(5(x+1))] =
    (4/3) * (6/5) = 24/15 = 8/5

    x must be different then 1 and -1.
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