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Math Help - This Linear Equation Answer Can't be Correct

  1. #1
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    This Linear Equation Answer Can't be Correct

    Linear Equation: 7x+5/3=11 Answer: x=4/3 ... I'm not getting that answer and don't know in which step I went wrong.

    Can someone expand and this and show me how the solution was derived. Thank you!
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    Re: This Linear Equation Answer Can't be Correct

    Multiply through by 3.

    21x+5=33

    Can you do it from there?
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    Re: This Linear Equation Answer Can't be Correct

    You can also do like this
    take away 5/3 on both side then you got
    7x=11-5/3
    can u finish this?
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    Re: This Linear Equation Answer Can't be Correct

    can you show me your progress so i can say what u did wrong ? its better if i help you with your progress
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    Re: This Linear Equation Answer Can't be Correct

    Quote Originally Posted by Petrus View Post
    can you show me your progress so i can say what u did wrong ? its better if i help you with your progress
    I'm struggling with 9th grade math :-(

    But here's how I did it: 3+5*7x/3=11

    3+35x/3=11

    3+35x=3*11

    3+35x=33

    -3 3+35x=33 -3

    35x = 30

    x = 35/30...

    I don't understand the sequence of numbers you have to either add or multiply when solving the equation. How do I know what to multiply with such equations?
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  6. #6
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    Re: This Linear Equation Answer Can't be Correct

    the misstake u do is that u cant multiplicate 7x with 5 :P your method seems like a tutor its simple look at his tips!
    dw i also sometimes struggle with 9th grade mat
    Last edited by Petrus; November 5th 2012 at 05:24 AM.
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  7. #7
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    Re: This Linear Equation Answer Can't be Correct

    Quote Originally Posted by MathClown View Post
    Linear Equation: 7x+5/3=11 Answer: x=4/3 ... I'm not getting that answer and don't know in which step I went wrong.

    Can someone expand and this and show me how the solution was derived. Thank you!
    first off, is the equation

    \frac{7x+5}{3} = 11

    or

    7x + \frac{5}{3} = 11


    ???
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    Re: This Linear Equation Answer Can't be Correct

    Quote Originally Posted by skeeter View Post
    first off, is the equation

    \frac{7x+5}{3} = 11

    or

    7x + \frac{5}{3} = 11


    ???
    The equation is the FIRST one you posted. Sorry for the ambiguity. Can you lend me hand with it?
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  9. #9
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    Re: This Linear Equation Answer Can't be Correct

    if the equation is
    \frac{7x+5}{3} = 11
    then that x=4/3 is wrong answer
    if we multiplicate with 3 then we get
    \frac{7x+5}{1} = 33 (why i got divide by 1 is because im not good with that latex code.. it get strange if i take away 1 but you understand)
    can you finish this?
    Last edited by Petrus; November 5th 2012 at 06:43 AM.
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    Re: This Linear Equation Answer Can't be Correct

    Quote Originally Posted by MathClown View Post
    The equation is the FIRST one you posted. Sorry for the ambiguity. Can you lend me hand with it?
    x = 4/3 is the correct answer for the second equation. Not the first one...something's wrong here.
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  11. #11
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    Re: This Linear Equation Answer Can't be Correct

    Quote Originally Posted by MathClown View Post
    The equation is the FIRST one you posted. Sorry for the ambiguity.
    next time use grouping symbols to make your equation clear to those who read it ...

    Linear Equation: (7x+5)/3=11
    \frac{7x+5}{3} = 11

    multiply both sides by 3 to clear the fraction ...

    7x+5 = 33

    subtract 5 from both sides ...

    7x = 28

    divide both sides by 7 ...

    x = 4

    substitute your solution back into the original equation to check ...

    \frac{7(4)+5}{3} = \frac{28+5}{3} = \frac{33}{3} = 11
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