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Math Help - Need some help simplifying

  1. #1
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    Need some help simplifying

    Having problems with these 3
    1.
    x2-x-2 x2-x-20
    X
    x2+x-6 x2+5x+4 Simplify

    2. 1 = 1 6
    x-1 2x+3 (2x+3)(x-1) :Solve

    3. Brad is (now) 3 years older than janet. Janet's age 2 years from now (future) will be 8/9 of brad's age 2 years from now. How old are they now?

    Thanks for any help
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  2. #2
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by ls1ramair19 View Post
    Having problems with these 3
    1.
    x2-x-2 x2-x-20
    X
    x2+x-6 x2+5x+4 Simplify

    2. 1 = 1 6
    x-1 2x+3 (2x+3)(x-1) :Solve

    3. Brad is (now) 3 years older than janet. Janet's age 2 years from now (future) will be 8/9 of brad's age 2 years from now. How old are they now?

    Thanks for any help
    Can you rewrite problems 1 and 2 please. For x squared write x^2. and for something divided by something write something/something. 'cause the forum right aligns everything, so its distorted and i really dont know what's going on.

    For 3. though:

    Let x be Brad's age. Then x - 3 is Janet's age. 2 years from now, Janet will be x - 3 + 2 = x - 1 = (8/9)(x + 2) = (8x + 16)/9

    So the equation we want to solve is x - 1 = (8x + 16)/9.
    => 9x - 9 = 8x + 16
    => x = 25

    So their ages now are, Brad: 25, Janet 22.
    Last edited by Jhevon; February 25th 2007 at 02:00 PM.
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  3. #3
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    1.
    x^2-x-2 Times x^2-x-20
    x^2+x-6SPACE x^2+5x+4 Simplify

    2.
    1/x-1= 1/2x+3 + 6/(2x+3)(x-1) solve:
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  4. #4
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by ls1ramair19 View Post
    1.
    x^2-x-2 Times x^2-x-20
    x^2+x-6SPACE x^2+5x+4 Simplify

    2.
    1/x-1= 1/2x+3 + 6/(2x+3)(x-1) solve:


    1. (x^2 - x - 2)/(x^2 + x - 6) times (x^2 - x - 20)/(x^2 + 5x + 4)

    => [(x - 2)(x + 1)]/[(x - 2)(x + 3)] times [(x - 5)(x + 4)]/[(x + 1)(x + 4)]

    The (x - 2)'s cancel from the first fraction and the (x + 4)'s cancel from the second.

    So we have (x + 1)/(x + 3) times (x - 5)/(x + 1)
    => [(x + 1)(x - 5)]/[(x + 1)(x + 3)]

    The (x + 1)'s cancel leaving (x - 5)/(x + 3)



    2. 1/(x - 1) = 1/(2x + 3) + 6/(2x + 3)(x - 1)
    multiplying through by (2x + 3)(x - 1) we obtain:

    2x +3 = x - 1 + 6
    =>2x + 3- x = -1 + 6
    => x = 2
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  5. #5
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by ls1ramair19 View Post
    1.
    x^2-x-2 Times x^2-x-20
    x^2+x-6SPACE x^2+5x+4 Simplify

    2.
    1/x-1= 1/2x+3 + 6/(2x+3)(x-1) solve:


    If you dont see why i multiplied by (2x + 3)(x - 1) in 2. An alternate method may help you see why.

    What you could do is bring the 1/(2x +3) over the equal sign to obtain:

    1/(x - 1) - 1/(2x +3) = 6/(2x + 3)(x - 1)

    we see if we add the left side, we will get a fraction where the lcm is the same as the right, so the denominators of both fractions will be the same, so the numerators can be equated. So we would end up with the line:

    2x + 3 - x + 1 = 6
    => x = 2
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  6. #6
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    Thank you very much you explained it a lot better than my teacher could
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  7. #7
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by ls1ramair19 View Post
    Thank you very much you explained it a lot better than my teacher could
    I hope so. Don't just read through it though. Try to work through it. Try both methods and see which one you like better. and then if you come up on any problems, just post a reply.
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