(1)X/Y=3/2 Y/X=2/3
(x/y-y/x)÷ (x/y+y/x-2)÷ (1+y/x) =(3/2-2/3)/(3/2+2/3-2)/(1+2/3)=3
(2) [(2a+1/2a-1)-(2a-1/2a+1)]÷ [1÷ (1-1/a+1/4a^2)]=-6
(3) 因为a^2-2a-8=0所以a=4或a=-2
(1)X/Y=3/2 Y/X=2/3
(x/y-y/x)÷ (x/y+y/x-2)÷ (1+y/x) =(3/2-2/3)/(3/2+2/3-2)/(1+2/3)=3
(2) [(2a+1/2a-1)-(2a-1/2a+1)]÷ [1÷ (1-1/a+1/4a^2)]=-6
(3) 因为a^2-2a-8=0所以a=4或a=-2