more math

Discussion in 'The Okie Corral' started by Atomic Punk, Apr 4, 2012.

  1. Atomic Punk

    Atomic Punk

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    brushing up on some math. have a test for a new job in a few weeks. got some sample questions. i am out of practice but i can figure most of it out. one of the questions i still dont get though.

    Y= 3(x+5) (x-2)

    multiple choice. wants a formula that is equivalent. says the answer is

    Y= 3x2 + 9x - 30

    can anyone explain how this works?
     
  2. TalkToTheGlock

    TalkToTheGlock Zombie Hunter

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    Multiply 3 by (x+5). Equals (3x+15). Then use distributive property to multiply the values (3x + 15) times (x - 2).

    Equals..

    3x2 - 6x +15x -30. The add equal or like terms and get...


    3x2 + 9x -30


    iPhone 4
     

  3. Blaster

    Blaster Hunc tu caveto

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    Y= 3(x+5) (x-2)

    Y= (3x+15) (x-2)

    next FOIL (First Inner Outer Last)

    Y= 3x2 + 15x - 6x -30

    Y= 3x2 + 9x - 30
     
  4. TalkToTheGlock

    TalkToTheGlock Zombie Hunter

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    And let me add this...

    You need to multiply 3x by x And then by negative 2. Then you do the same for 15 and bingo. Hopw I helped.


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  5. ArtificialGrape

    ArtificialGrape CLM

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    3(x+5) (x-2)

    Multiply 3 times the expression (x + 5) and right hand becomes

    (3x + 15) (x - 2)

    Now apply F.O.I.L. -- multiply Firsts, then Outers, then Inners, then Lasts

    Firsts = 3x times x = 3x^2
    Outers = 3x times -2 = -6x
    Inners = 15 times x = 15x
    Lasts = 15 times -2 = -30

    add them all up for
    3x^2 + 9x -30

    Good Luck.
     
    Last edited: Apr 4, 2012
  6. Atomic Punk

    Atomic Punk

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    thank you. i will have to go over it a few times to get it down. but its all there.