Răspuns :
(y²-x²)/(x²-yx)=
=(y+x)(y-x)/(-x)(-x+y)=
=(y+x)(y-x/(-x)(y-x)=
=(y+x)/(-x)=-y/x-1
=(y+x)(y-x)/(-x)(-x+y)=
=(y+x)(y-x/(-x)(y-x)=
=(y+x)/(-x)=-y/x-1
(y²-x²)/(x²-yx)=
=(y+x)(y-x)/(-x)(-x+y)=
=(y+x)(y-x/(-x)(y-x)=
=(y+x)/(-x)=-y/x-1