f(1)=a+b+c=-a,2a+b+c=0 => c=-2a-b
3a>2b,3a>c=-2a-b,2b>c=-2a-b;
a>2b/3,5a>-b,3b>-2a;
=>a>2b/3,a>-b/5,a>-3b/2
1.a>0,则 b/a-5,b/a>-2/3
=> -2/3
f(1)=a+b+c=-a,2a+b+c=0 => c=-2a-b
3a>2b,3a>c=-2a-b,2b>c=-2a-b;
a>2b/3,5a>-b,3b>-2a;
=>a>2b/3,a>-b/5,a>-3b/2
1.a>0,则 b/a-5,b/a>-2/3
=> -2/3