a=(9/5)*(a-2)*(a-m) ----------(1)
a=(9/5)*(1/a-2)*(1/a-m) ----------(2)
显然有(a-2)*(a-m)=（1/a-2)*(1/a-m)
a^2-(2+m)a+2m=(1/a)^2-(2+m)*(1/a)+2m
a^2-(1/a)^2-(2+m)a-(2+m)*(1/a)=0
(a-1/a)(a+1/a-2-m)=0
a=1或-1或a+1/a-2-m=0 当a=1或-1时直接代入可得m=14/9 或者-32/27
当a+1/a-2-m=0时即m=a+1/a-2 代入（1）有
a=9/5*(a-2)*(a-a-1/a+2) 5a=(a-2)*(2-1/a) 5a^2=(a-2)(2a-1)
13a^2-45a+18=0