How to solve 5 equations with 5 unknowns

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Hinko Fic
Hinko Fic on 29 May 2015
Answered: Alex Sha on 12 Oct 2019
Hi, I don't have any idea how to solve this system. I'm beginner so i don't knew how to write corect code. Pls help me. Equations:
(A-B-C)*5=C*6 ////
(A-B-C)*2+B*3=(A-B)*D ////
(A-B)*(2-D)=B*3 ////
(A-B)*2+B*4=B*E ////
A*2+(A-B)*3+(A-B-C)*2=50
  7 Comments
Roger Stafford
Roger Stafford on 11 Mar 2018
I don't remember this problem from almost two years ago, but apparently all of us (except perhaps Muhammad Saleem) overlooked the fact that it is actually a system of five linear equations in the five unknown quantities, A, B, C, d=(A-B)*D, and e=B*E, so it can be solved for these latter five variables using matrix division. From those solutions, it is easy to then find D and E: D = d/(A-B) and E = e/B.

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Accepted Answer

Roger Stafford
Roger Stafford on 29 May 2015
Edited: Roger Stafford on 29 May 2015
You can use 'solve' in the Symbolic Toolbox to solve them.
My alternate method was in error. Just use 'solve'. It does very well.
  5 Comments
Hinko Fic
Hinko Fic on 30 May 2015
That works, ty a lot, you saved me a lot of time

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More Answers (1)

Alex Sha
Alex Sha on 12 Oct 2019
Numercial solution:
a: 9.00473933649289
b: 1.18483412322275
c: 3.55450236966825
d: 1.54545454545455
e: 17.2

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