Results 1 to 6 of 6

Math Help - Distributing and simplifying

  1. #1
    Senior Member vaironxxrd's Avatar
    Joined
    Nov 2010
    From
    USA
    Posts
    424
    Thanks
    1
    Awards
    1

    Distributing and simplifying

    4(3x-5)= -2(-x+8)

    I got 10x= 4
    = 2.5
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Prove It's Avatar
    Joined
    Aug 2008
    Posts
    11,407
    Thanks
    1294

    Re: Distributing and simplifying

    Quote Originally Posted by vaironxxrd View Post
    4(3x-5)= -2(-x+8)

    I got 10x= 4
    = 2.5
    \displaystyle \begin{align*} 4(3x-5) &= -2(-x+8) \\ 12x-20 &= 2x-16\\ 10x-20 &= -16\\ 10x &= 4 \\ x &= \frac{4}{10} \\ x &= \frac{2}{5}\end{align*}

    I disagree with your answer of \displaystyle x = 2.5
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Senior Member vaironxxrd's Avatar
    Joined
    Nov 2010
    From
    USA
    Posts
    424
    Thanks
    1
    Awards
    1

    Re: Distributing and simplifying

    Quote Originally Posted by Prove It View Post
    \displaystyle \begin{align*} 4(3x-5) &= -2(-x+8) \\ 12x-20 &= 2x-16\\ 10x-20 &= -16\\ 10x &= 4 \\ x &= \frac{4}{10} \\ x &= \frac{2}{5}\end{align*}

    I disagree with your answer of \displaystyle x = 2.5


    Oh so I was pretty close . One more question when 10x/4 you divide by 10 to get x by itself?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor Siron's Avatar
    Joined
    Jul 2011
    From
    Norway
    Posts
    1,250
    Thanks
    20

    Re: Distributing and simplifying

    Quote Originally Posted by vaironxxrd View Post
    Oh so I was pretty close . One more question when 10x/4 you divide by 10 to get x by itself?
    Do you mean:
    \frac{\frac{10x}{4}}{10}?
    Because that's not just x but \frac{\frac{10x}{4}}{10}=\frac{x}{4}
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Senior Member vaironxxrd's Avatar
    Joined
    Nov 2010
    From
    USA
    Posts
    424
    Thanks
    1
    Awards
    1

    Re: Distributing and simplifying

    Quote Originally Posted by Siron View Post
    Do you mean:
    \frac{\frac{10x}{4}}{10}?
    Because that's not just x but \frac{\frac{10x}{4}}{10}=\frac{x}{4}
    So your telling me its basically 10x/4/10? That looks weird
    Follow Math Help Forum on Facebook and Google+

  6. #6
    -1
    e^(i*pi)'s Avatar
    Joined
    Feb 2009
    From
    West Midlands, England
    Posts
    3,053
    Thanks
    1

    Re: Distributing and simplifying

    Quote Originally Posted by vaironxxrd View Post
    Oh so I was pretty close . One more question when 10x/4 you divide by 10 to get x by itself?
    10x/4 has to equal something though. In this case it is equal to 1 because you've brought the 4 from the RHS onto the LHS by division: \dfrac{10}{4} x = 1. From here you'd need to divide both sides by 10/4: x = \dfrac{1}{\left(\frac{10}{4}\right)} and since we divide fractions by "flip n multiply" the RHS is the same as 1 \times \dfrac{4}{10} = \dfrac{4}{10}



    From the line 10x = 4 you can divide both sides by 10 because we want to get x on it's own (which is the same as 1x): \dfrac{10x}{10} = \dfrac{4}{10} and since 10/10 is indeed 1 this is the same as \dfrac{4}{10} which is correct but it's more proper to simplify fractions and so 2/2 was cancelled.

    \dfrac{4}{10} = \dfrac{2 \times 2}{2 \times 5} = \dfrac{2}{5}.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Distributing different objects
    Posted in the Discrete Math Forum
    Replies: 2
    Last Post: April 29th 2011, 02:00 AM
  2. distributing on Ti-84 plus
    Posted in the Calculators Forum
    Replies: 6
    Last Post: August 30th 2009, 12:37 PM
  3. Distributing negatives
    Posted in the Algebra Forum
    Replies: 1
    Last Post: October 29th 2008, 09:04 AM
  4. Distributing
    Posted in the Algebra Forum
    Replies: 7
    Last Post: August 21st 2008, 10:30 AM
  5. Distributing with fractions
    Posted in the Math Topics Forum
    Replies: 3
    Last Post: July 6th 2008, 01:33 PM

Search Tags


/mathhelpforum @mathhelpforum