a十a十a=60,A十B十b二30,b一C二3,D十axE二几

,设x=1,得出a+b+c+d+e=-1设x=0，得出e=-2，设x=-1，得出a-b+c-d+e=-3,两个方程相加，得出2（a+c）+2e=-2(a+c)-4=4,得出a+c=0