Помогите упростить выражение! 4) а,б,
2a/(a-5)-5/(a+5) -2a²/(a-5)(a+5)=(2a²+10a-5a+25-2a²)/(a-5)(a+5)=(5a+25)/(a-5)(a+5)= =5(a+5)/(a-5)(a+5)=5/(a-5) 1)(x+y)/(x-y) - (x-y)/(x+y)=(x²+2xy+y²-x²+2xy-y²)/(x²-y²)=4xy/(x²-y²) 2)4xy/(x²-y²) : xy/(x²-y²)=4xy/(x²-y²) *(x²-y²)/xy=4