1
1)1/[(a-b)(a+b)]+b/[(a+b(*a²-ab+b²)]=(a²-ab+b²+ab-b²)/[(a-b)(a+b)(a²-ab+b²)]=
=a²/[(a³+b³)(a-b)]
2)a²/[(a-b)(a³+b³)] *(a³-b³)(a³+b³)/a²=(a³-b³)/(a-b)=(a-b)(a²+ab+b²)/(a-b)=a²+ab+b²
2
1)6a/[(a-2b)(a+2b)-2/(a-2b)-4/(a+2b)=(6a-2a-4b-4a+8b)/[(a-2b)(a+2b)]=
=4b/*a-2b)(a+2b)]
2)1+(a²+4b²)/(4b²-a²)=(4b²-a²+a²+4b²)=8b²/(4b²-a²)
3)-4b/(4b²-a²)*(4b²-a²)/8b²=-1/2b
3
1)y/[x(xy-²-xy+y²)]+(x-2y)/[(x+y)(x²-xy+y²)]=(xy+y²+x²-2xy)/[x*x+y)(x²-xy+y²)]
=(x²-xy+y²)/[x(x+y)(x²-xy+y²)]=1/[x(x+y)]
2)1/[x(x+y)]*x(x-y)(x+y)/(x²+y²(=(x-y)/(x²+y²)
3)(x-y)/(x²+y²)+2y²/[x²(x+y)+y²(x+y)]=(x-y)/(x²+y²)+2y²/[(x²+y²)(x+y)]=
=(x²-y²+2y²)/[(x²+y²)(x+y)]=(x²+y²)/[(x²+y²)(x+y)=1/(x+y)