Error solving equation in CAS

[toperos]

Hello,

I'm trying to find the solutions of the equation:
{(3,068e-3/(0.118+1,001e-5*X))-[[(1+2,126e-5*X)/(1+8,506e-5*X)]-[0.3+2,55e-5*X]]}=0

When i do it in CAS mode with "solve(equation,x)" i get as solutions {-9413.99 ; 15254.47}

And doing the same in non CAS with "FNROOT(equation,X)" i get 12055.26; this is the good solution(I have seen it plotting), but i only get the positive one.

I don't understand what happens or if I am doing something wrong.