$解:(2)由(1),得\begin{cases}{a+b+c=-a}\\{ab+ac+bc=b}\\{abc=-c}\end{cases}$
$①若c =0,则\begin{cases}{a+b=-a}\\{ab=b}\end{cases}$
$解得\begin{cases}{a=0}\\{b=0}\end{cases}, 或\begin{cases}{a=1}\\{b=-2}\end{cases}$
$∵a,b,c 不全为0$
$∴\begin{cases}{a=0}\\{b=0}\end{cases}不合题意,舍去$
$∴\begin{cases}{a=1}\\{b=-2}\\{c=0}\end{cases}$
$②若c≠0,则ab= -1$
$∵a,b都是整数$
$∴a=1,b=-1或a = - 1,b = 1$
$当 a = 1,b = - 1 时$
$\begin{cases}{1+(-1)+c=-1}\\{-1+c+(-c)=-1}\end{cases},解得c=-1;$
$当a=-1,b=1时$
$\begin{cases}{-1+1+c=1}\\{-1-c+c=1}\end{cases},该方程组无解$
$综上所述,a=1,b=-2,c=0$
$或a=1,b=-1,c=-1$