3a²-2a-1=0,十字相乘法分解
(3a+1)(a-1)=0
3a+1=0,a-1=0
a1=-1/3,a2=1
a有两个解,是-1/3或1
补充题:
因为3a²-2a-1=0
所以2a-3a²=-1
当a=-1/3时:
a²(2a-3a²)^2011+2a/3
=(-1/3)²(-1)^2011+(-1/3)×2/3
=1/9×(-1)-2/9
=-1/9-2/9
=-1/3
当a=1时:
a²(2a-3a²)^2011+2a/3
=1²×(-1)^2011+1×2/3
=-1+2/3
=-1/3