To find all triples (a,b,c) of real numbers satisfying the system of equations:
1.2.3.a2+ab+c=0,b2+bc+a=0,c2+ca+b=0,
we proceed by considering possible symmetric solutions first and also evaluate the possibility of all variables being zero.
### Step 1: Checking the trivial solution (0,0,0)
Substituting a=0, b=0, c=0 into the equations, we find:
02+0⋅0+002+0⋅0+002+0⋅0+0=0,=0,=0.
Since all the equations are satisfied, (0,0,0) is a valid solution.
### Step 2: Considering symmetric solutions where a=b=c=x
Assume a=b=c=x. Then the equations become:
x2+x⋅x+xx2+x⋅x+xx2+x⋅x+x=0⇒2x2+x=0,=0⇒2x2+x=0,=0⇒2x2+x=0.
Each equation simplifies to:
2x2+x=0
Factoring gives:
x(2x+1)=0
Thus, the solutions for x are x=0 or x=−21.
- For x=0, this corresponds to the solution (0,0,0).
- For x=−21, this gives the solution (−21,−21,−21).
Both solutions satisfy the original equations, since substituting back verifies equality:
(−21)2+(−21)(−21)+(−21)(−21)2+(−21)(−21)+(−21)(−21)2+(−21)(−21)+(−21)=41+41−21=0,=0,=0.
### Final Solutions
Thus, the complete set of solutions for (a,b,c) is:
(0,0,0)and(−21,−21,−21)