А
1)(x+10)/[5(x+5)]-1/(x+5)=(x+10-5)/[5(x+5)]=(x+5)/[5(x+5)]=1/5
2)1/5*5/(x-5)=1/(x-5)
3)1/(x-5)-10/[(x-5)(x+5)]=(x+5-10)/[(x-5)(x+5)]=(x-5)/[(x-5)(x+5)]=1/9x+5)
б
1)2/[y(2-y)]-1/(2-y)=(2-y)/[y(2-y)]=1/y
2)1/(y²-1)*y=y/(y²-1)
3)y²/(y²-1)-y/(y²-1)=(y²-y)/(y²-1)=y(y-1)/[(y-1)(y+1)]=y/(y+1)