a²+b²=(10/3)ab
同时除以b²
(a/b)²+1-(10/3)(a/b)=0
(a/b-3)(a/b-1/3)=0
解得
a/b=3或1/3
a-b分之a+b
=(a+b)/(a-b)
=(a/b+1)/(a/b-1)
=2或-2