Results 1 to 3 of 3

Math Help - Linear Equation question

  1. #1
    Member
    Joined
    May 2008
    Posts
    143

    Linear Equation question

    When using the formula  A=\frac{1}{2}(a+b)h when solving for b this equals

    \frac{2}{h}(A-\frac{ah}{2})=b why do we not distribute the \frac{2}{h} over the parenthesis?

    If we were to distribute it I think it would look like this, please correct me if I am mistaken.
    <br />
\frac{A}{1}*\frac{2}{h}-\frac{ah}{h}*\frac{2}{h}=\frac{2A}{h}-a=b, if this is correct the book does not list it as an answer choice.

    Thank you
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Mar 2009
    From
    Alberta
    Posts
    173
    Quote Originally Posted by allyourbass2212 View Post
    When using the formula  A=\frac{1}{2}(a+b)h when solving for b this equals

    \frac{2}{h}(A-\frac{ah}{2})=b why do we not distribute the \frac{2}{h} over the parenthesis?

    If we were to distribute it I think it would look like this, please correct me if I am mistaken.
    <br />
\frac{A}{1}*\frac{2}{h}-\frac{ah}{h}*\frac{2}{h}=\frac{2A}{h}-a=b, if this is correct the book does not list it as an answer choice.

    Thank you
    It's probably just them stopping one step short, you could simplify that to what you did (Which we can verify), but it's purely aesthetic.

    Though, you did have a small mistake in your simplification, which was probably just a mis-type.

    <br />
\frac{A}{1}*\frac{2}{h}-\frac{ah}{2}*\frac{2}{h}=\frac{2A}{h}-a=b

    It should be \frac{ah}{2} not \frac{ah}{h}.

    That said, we can verify that your simplification is a correct one by choosing arbitrary values for the equations, as long as we use the same values for both equations, if they put out the same answer, they are equivalent.

    For this, we will make a=2 , h=2 , and A=10

    Original equation;

    <br />
\frac{2}{h}(A-\frac{ah}{2})=b

    \frac{2}{2}(10-\frac{4}{2})=b

    b=8

    Your simplification;

    \frac{2A}{h}-a=b

    \frac{2(10)}{2}-2=b

    b=8

    Because they both give the same answer with the same variable values, they are equivalent.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    May 2008
    Posts
    143
    Yes that was a typo, and thank you very much!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Question with linear Diophantine equation
    Posted in the Number Theory Forum
    Replies: 2
    Last Post: January 18th 2010, 07:40 PM
  2. Linear Diophantine Equation question
    Posted in the Number Theory Forum
    Replies: 2
    Last Post: January 18th 2010, 06:45 PM
  3. set of linear equation question..
    Posted in the Calculus Forum
    Replies: 0
    Last Post: December 9th 2008, 10:52 AM
  4. Simple question regarding linear equation ?
    Posted in the Algebra Forum
    Replies: 2
    Last Post: November 13th 2008, 01:45 AM
  5. Linear equation question
    Posted in the Algebra Forum
    Replies: 8
    Last Post: July 6th 2007, 03:40 PM

Search Tags


/mathhelpforum @mathhelpforum