Results 1 to 2 of 2

Math Help - A simple matrix help

  1. #1
    Junior Member
    Joined
    May 2009
    Posts
    28

    A simple matrix help

    Hi . can anyone tell me the steps to do a matrix like this, its a bit confusing.

    Given That : top: a + b 2a-8
    bottom: a - b 0

    = top 7 2
    bottom 3 0

    find a and b

    sorry for not using latex but the code is a bit complicated...
    they are all 2 * 2 matrix with a + b , 2a-8 on top for the first matrix
    a-b , 0 in the bottom of the first matrix

    and the second matrix is 7 , 2 on top and 3, 0 in the bottom

    they are seperated by a equals sign

    they question is to find a and b
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Apr 2005
    Posts
    15,775
    Thanks
    1514
    Quote Originally Posted by llkkjj24 View Post
    Hi . can anyone tell me the steps to do a matrix like this, its a bit confusing.

    Given That : top: a + b 2a-8
    bottom: a - b 0

    = top 7 2
    bottom 3 0

    find a and b

    sorry for not using latex but the code is a bit complicated...
    they are all 2 * 2 matrix with a + b , 2a-8 on top for the first matrix
    a-b , 0 in the bottom of the first matrix

    and the second matrix is 7 , 2 on top and 3, 0 in the bottom

    they are seperated by a equals sign

    they question is to find a and b
    So
    \begin{bmatrix}a+ b & 2a- 8 \\ a- b & 0\end{bmatrix}= \begin{bmatrix}7 & 2 \\ 3 & 0\end{bmatrix}
    (click on that to see the LaTex code I used.)

    Since equality for matrices is defined to mean that all corresponding entries are equal, that tells you that a+ b= 7, 2a- 8= 2, a- b= 3, and 0= 0. Since that is three equations ("0= 0" is always true, of course) for two unknown values, it may be "over determined", that is, there may not be 2 numbers that satisfy all three equations.

    I recommend starting by adding the first and third equations. That will immediately eliminate b and you can solve for a. The use any one of the equation to find the value of b for that a. Finally, check that all equations are satified.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Simple Matrix Proof
    Posted in the Advanced Algebra Forum
    Replies: 2
    Last Post: September 15th 2011, 12:02 PM
  2. simple ODE with matrix
    Posted in the Differential Equations Forum
    Replies: 0
    Last Post: February 9th 2011, 12:14 PM
  3. Simple matrix problem
    Posted in the Advanced Algebra Forum
    Replies: 2
    Last Post: February 18th 2010, 12:42 PM
  4. simple matrix question
    Posted in the Algebra Forum
    Replies: 2
    Last Post: April 16th 2008, 02:05 AM
  5. a simple matrix question
    Posted in the Advanced Algebra Forum
    Replies: 1
    Last Post: October 31st 2007, 07:14 PM

Search Tags


/mathhelpforum @mathhelpforum