Decimal problem using solve

[vterez]

(08-26-2018 07:22 PM)Albert Chan Wrote:  If it were homework, I think it meant not using SOLVE, calculator only for number crunching.
You really should do y = 1/(23000+z), and simplified it by hand:

70*y = x*177.35+(1-x)*1.133
(x*2571.11+(1-x)*696.21) = (2779.65*(23000+z) + 23000*(104.91-2779.65)) / (23000+z) = 2779.65 - 61519020*y

Above simplified to linear equations:
70*y = 1.133 + 176.217*x
61519020*y = 2083.44 - 1874.9*x

Cancel the y's --> x ~ -0.00641604 --> z ~ 6358.11

Regarding the {} answer, I believe SOLVER assumed decimals as float, to speed up calculation.
Slight rounding error cause above into nonlinear equations.

I did solve it myself, I was just checking my results.
I love to solve math problems by hand (I swear I spend some free time playing with matrixes and finding zeros for some equations) but since this was just a small part of the problem and it is not for math class, is for advanced circuit analysis, I wouldn't mind using my calculator to solve it. I am almost graduating in Electrical Engineering and my teachers tell the students to use computer solving to save time (which is a relief when I stumble across some really annoying problems involving complex numbers).