a等于198
a+b+c=297;a=3b;a=6c;a+1/3a+1/6a=297;3/2a=297;a=198
297÷(1+1/3+1/6)=198
解: b=a/3, c=a/6a+b+c=a+a/3+a/6=a(1+1/3+1/6)=3a/2=297a=198
