## gjhfdfg 2 years ago What am I doing wrong? (matrix question)

1. gjhfdfg

I have a matrix problem where I solve for X, the problem is 4X + A = B. I plugged my matrices into my calculator & typed 4x + a then pressed enter. Then it said error? Am I not doing this problem correctly?

2. gjhfdfg

Do I just subtract the 2 matrices from each other instead?

3. tyteen4a03

Did you define a and b?

4. gjhfdfg

Yes, a and b were already defined

5. tyteen4a03

What is the error message?

6. gjhfdfg

Just says error data type, 1.quit 2. go to

7. phi

matrix X is undefined, right ? I would try: enter matrix A and matrix B find B-A divide that by 4 that should give you X

8. phi

If these are small matrices, (if all else fails) you can do this by hand B-A means subtract corresponding elements

9. gjhfdfg

I got this from subtracting b & a, [5 3] [4 -6] [-5 0] & then I tried to divide that by 4 & it says error

10. phi

I don't know how your calculator works with matrices, but dividing a matrix by 4 means divide each of its elements by 4 (or multiply by 0.25) the first row would be 5/4 3/4 and so on...

11. gjhfdfg

Im using an ti-84 plus if that helps... It usually solves my problems, I don't understand why the error message keeps popping up

12. gjhfdfg

But I got my answer, thank you for help once again.!

13. phi

I just looked at the manual, and it should work. It does want the 4 to be a value (not a matrix) did you try multiplying by 0.25 (just an experiment)

14. gjhfdfg

Yes, multiplying it by 0.25 worked. Just the 4 by itself didnt

15. phi

go figure..

16. gjhfdfg

Odd