Results 1 to 2 of 2

Math Help - Simple algebra question.

  1. #1
    Junior Member
    Joined
    Sep 2009
    Posts
    34

    Simple algebra question.

    Please be understanding if this is a stupid question as I am making a comeback to algebra after 20 years of not using it.

    The following appears in my text book...
    \frac{x}{3\sqrt(100^2+x^2)}=\frac{1}{5}
    the next line is....
    5x=3\sqrt(100^2+x^2)
    it is the 5x which bothers me, I would have thought to multiply both sides by 3\sqrt(100^2+x^2) then divide both sides by \frac{1}{5} which would in my mind result in \frac{x}{5}=3\sqrt(100^2+x^2)
    Have I missed the point here?

    Splint
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Jan 2009
    Posts
    591
    Quote Originally Posted by Splint View Post
    Please be understanding if this is a stupid question as I am making a comeback to algebra after 20 years of not using it.

    The following appears in my text book...
    \frac{x}{3\sqrt(100^2+x^2)}=\frac{1}{5}
    the next line is....
    5x=3\sqrt(100^2+x^2)
    it is the 5x which bothers me, I would have thought to multiply both sides by 3\sqrt(100^2+x^2) then divide both sides by \frac{1}{5} which would in my mind result in \frac{x}{5}=3\sqrt(100^2+x^2)
    Have I missed the point here?

    Splint
    Division by \dfrac{1}{5} is equivalent to multiplication by 5.
    You have divided the RHS by \dfrac{1}{5},
    but
    you have divided the LHS by 5.


    You multiplied through with the square root part and had no problem -- follow that by multiply both sides by 5.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Simple Algebra Question
    Posted in the Algebra Forum
    Replies: 3
    Last Post: October 18th 2011, 04:12 PM
  2. Simple question about algebra y^T X y
    Posted in the Advanced Algebra Forum
    Replies: 1
    Last Post: November 17th 2010, 01:22 PM
  3. Simple Algebra Question
    Posted in the Algebra Forum
    Replies: 6
    Last Post: May 6th 2010, 09:00 PM
  4. simple algebra question
    Posted in the Algebra Forum
    Replies: 2
    Last Post: October 6th 2009, 04:35 AM
  5. Simple Algebra Question
    Posted in the Algebra Forum
    Replies: 3
    Last Post: March 27th 2009, 01:16 PM

Search Tags


/mathhelpforum @mathhelpforum