(a^2-a+1)^m·(a-a^2-1)^2m÷(a-a^2-1)^3m
=(a²-a+1)^m÷(a-a²-1)^m
=((a²-a+1)÷(a-a²-1))^m
=(-1)^m
m为奇数,原式=-1;
m为偶数,原式=1;