(x-2)/2010+x/2011+(x+2)/2012=6
另a=2011,则
(x-2)/(a-1)+x/a+(x+2)/(a+1)=6
[a(a+1)(x-2)+(a-1)(a+1)x+a(a-1)(x+2)]/[a(a-1)(a+1)]=6
a^2x+ax-2a^2-2a+a^2x-x+a^2x-ax+2a^2-2a=6a(a-1)(a+1)
3a^2x-x-4a=6a^3-6a
x=(6a^3-2a)/(3a^2-1)
=(6*2011^3-2*2011)/(3*2011^2-1)
=4022