# Urgent Help: Matrix Addition For X And Y

• Sep 21st 2006, 07:46 AM
dekorn24
Urgent Help: Matrix Addition For X And Y
I am suppose to find x and y in the matrix addition problem but just cant get anywhere. The problem is

Code:

```[2x  4] + [3y  -2] = [-5  2] [-3  5x] + [-2  3]  [-5  13]```
I know that you add 2x+3y = -5 and 4 +-2 etc. but how can I solve for x and y when there is no y on the bottom.

*I dont have brackets around, but the 2 matrix are 2x2 to = 2x2*
• Sep 21st 2006, 07:56 AM
Plato
If you did not leave a y of the second matrix, then all you have to do is solve:
2x+3y=-5
5x+3=13.
• Sep 21st 2006, 08:01 AM
CaptainBlack
Quote:

Originally Posted by dekorn24
I am suppose to find x and y in the matrix addition problem but just cant get anywhere. The problem is

Code:

```[2x  4] + [3y  -2] = [-5  2] [-3  5x] + [-2  3]  [-5  13]```
I know that you add 2x+3y = -5 and 4 +-2 etc. but how can I solve for x and y when there is no y on the bottom.

*I dont have brackets around, but the 2 matrix are 2x2 to = 2x2*

Write out all the simple equations:

2x+3y=-5
4-2=2
-3-2=-5
5x+3=13.

The second and third tell you nothing about x and y, but the fourth
equation tells you that x=5, and substituting this into the first equation
gives:

10+3y=-5,

so y=-15.

RonL