你连题都写错了设a=2011
则可变为 （a-3）（a-1）（a+1）（a+3）+16
=（a-3）（a+3）（a-1）（a+1）+16
=(a*a-1)(a*a-9)+16
=a^4-10a^2+25
=（a^2-5）^2