The solutions are (a,b,c)=(1,0,0),(2,−1,−1) up to permutation.
Let s=a+b+c. Consider
P(x)=(x−a)(x−b)(x−c)=x3−sx2+(ab+bc+ca)x−abc.
Putting x=s, we obtain (b+c)(c+a)(a+b)=(ab+bc+ca)s−abc. Therefore, the given equation becomes
(ab+bc+ca)s−abc+2s3=2−2abc.
This is the same as −s3−s3−(ab+bc+ca)s−abc=−2, i.e. P(−s)=−2. In other words, we have
(2a+b+c)(a+2b+c)(a+b+2c)=2.
(One can prove this by direct expansion.) By symmetry, it suffices to consider a few cases as follows.
* If 2a+b+c=2 and a+2b+c=a+b+2c=1, adding these we obtain 4(a+b+c)=4. So we have a+b+c=1, and hence (a,b,c)=(1,0,0).
* If 2a+b+c=2 and a+2b+c=a+b+2c=−1, adding these we obtain 4(a+b+c)=0. So we have a+b+c=0, and hence (a,b,c)=(2,−1,−1).
* If 2a+b+c=−2, a+2b+c=±1 and a+b+2c=∓1, adding these we obtain 4(a+b+c)=−2. There is no integer solution.
This shows the only solutions are (a,b,c)=(1,0,0),(2,−1,−1) up to permutation.