x-5/x-3+x-11/x-9=x-9/x-7+x-7/x-5
（x-5)/(x-3)-(x-7)/(x-5)=(x-9)/(x-7)-(x-11)/(x-9)
4/(x-3)(x-5)=4/(x-7)(x-9)
(x-3)(x-5)=(x-7)(x-9)
8x=48
x=6