1
1)b/(b-c)²+b/[(b-c)(b+c)]=b(b+c+b-c)/[(b-c)²(b+c)]=2b²/[(b-c)²(b+c)]
2)(b-c)²/b*2b²/[(b-c)²(b+c)]=2b/(b+c)
3)2c/(b+c)-2b/(b+c)=(2c-2b)/(b+c)=2(c-b)/(b+c)
2
1)x/[(x-y)9x+y)]-x/(x-y)²=x(x-y-x-y)/[(x-y)²(x+y)]=-2xy/[(x-y)²(x+y)]
2)-2xy/[(x-y)²(x+y)]*(y-x)²/2x=-y/(x+y)
3)-y/(x+y)-x/(x+y)=(-y-x)/(x+y)=-(y+x)/(x+y)=-1