x/(2x-5)=5/(5-2x)
(5-2x)x=5(2x-5)
5x-2x^2=10x-25
2x^2-5x-25=0
(x-5)(2x+5)=0
x-5=0或2x+5=0
x=5或-5/2
x/(x-2)+2/(x^2-4)=1
x(x+2)+2=x^2-4
x^2+2x+2=x^2-4
2x=-6
x=-3