How to solve 5 equations with 5 unknowns

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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
Hinko Fic
Hinko Fic on 30 May 2015
Edited: Hinko Fic on 30 May 2015
Yeah, i knew how to solve linear, but this isn't. That's reason why i need help. I need to solve these equations with different numbers (more complicated) for my project in school
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
Walter Roberson
Walter Roberson on 30 May 2015
structfun(@double, sol, 'Uniform', 0)
will return back a structure whose fields are a, b, c, d, e. For any particular one of them you can use (e.g.) double(sol.b)
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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