Объяснение:
1) 3/(x+y)-5/x = 3x-5(x+y)=3x-5x-5y= -2x-5y;
2) 6/(m-1)-2/m=6m-2(m-1)=6m-2m+2=4m+2;
3) 4/(a-b)+1/a=4a+1(a-b) = 4a+a-b = 5a-b;
4) 1/(b+2)-3/b=b-3(b+2)=b-3b-6= -2b-6.
