Why the solution of a system of linear equations on MATLAB differs from Excel ?

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Wael Badr

and these are the solution vector from both MATLAB and EXCEL .

There are some differences due to approximation, but three values are totally different

Anton Vrdoljak

Hmm, all I can comment is that the differences are caused by numerical precision... Next, in both programs calculate matrix Y = AX, and compare it with your matrix B, maybe you can conclude smth from those results...

I agree it may be due to numerical precision, but the in the solution vector I shared here, the 3rd and 9th elements are totally different.

Thank you anyway for your help.

Another hint is to check the condition number of a matrix A.

https://www.mathworks.com/help/symbolic/cond.html

https://blogs.mathworks.com/cleve/2017/07/17/what-is-the-condition-number-of-a-matrix/