已知X2—4X+4與|Y—1|互為相反數則式子(X分子Y减去Y分子X)除(X+Y)的值等於?

已知X2—4X+4與|Y—1|互為相反數則式子(X分子Y减去Y分子X)除(X+Y)的值等於?

x^2-4x+4+|y-1|=0
(x-2)^2+|y-1|=0
(x-2)^2=0,|y-1|=0
x=2,y=1
(y/x-x/y)/(x+y)
=(y^2/xy-x^2/xy)/(x+y)
=[(y^2-x^2)/xy]/(x+y)
=(y-x)(y+x)/xy*1/(x+y)
=(y-x)/xy
=(1-2)/1*2
=-1/2