# Matrices problem

• December 2nd 2010, 03:32 PM
halloweengrl24
Matrices problem
Perform the operation for each equation, if there is a solution (Matrices)

[4k -8y ] [5k+6y 2k+1]
[6z - 3x ] - [2z+5x z+4 ]
[2k + 5a] [4k+6a 3a+2]
• December 6th 2010, 08:50 PM
dwsmith
I am not sure what is going on here.
• December 7th 2010, 04:01 AM
HallsofIvy
You appear to be trying to subtract two matrices but it is not clear whether the first matrix has two columns or only one.
If the first matrix has only one column, if the problem is
$\begin{bmatrix}4k- 8y \\ 6z- 3x \\ 2k+ 5a\end{bmatrix}- \begin{bmatrix}5k+ 6y & 2k+ 1 \\ 2z+ 5x & z+ 4 \\ 4k+ 6a & 3a+ 2\end{bmatrix}$
then the operation is impossible- you can only add or subtract matrices having the same number of rows and columns.

If the first matrix has two column, if the problem is
$\begin{bmatrix}4k & -8y \\6z & -3x \\ 2k & 5a\end{bmatrix}- \begin{bmatrix}5k+ 6y & 2k+ 1 \\ 2z+ 5x & z+ 4 \\ 4k+ 6a & 3a+ 2\end{bmatrix}$
then the subtraction is "term by term"- subtract corresponding terms:
$\begin{bmatrix}4k- 5k0 6y & -8y- 2k- 1 \\ 6z-2z- 5x & -3x- z- 4 \\ 2k- 4k- 6a & 5a- 3a- 2\end{bmatrix}$.

Now my question is "why are you posting that here?". If you are attempting such a problem, surely you have seen the definition of matrix addition and subtraction? And that is all that is required here.