Алгебра 8 класс. посчитайте

1) -y/x

2)1/a²+ab+b²

1) x/y-y/x= x²-y²/xy=(x-y)(x+y)/xy

(x-y)(x+y)/xy×y/x+y=x-y/x

x-y/x-1=-y/x

2)2ab/(a-b)(a²+ab+b²)+a-b/a²+ab+b²=2ab+a²-2ab+b²/(a-b)(a²+ab+b²)=a²+b²/(a-b)(a²+ab+b²)

a²+b²/(a-b)(a²+ab+b²)×a-b/a²+b²=1/a²+ab+b²

3) 1/x+1+1/x-1=x-1+x+1/(x+1)(x-1)=2x/x²-1

1/x+2+1/x-2=2x/(x²-4)

2x/x²-4-2x/x²-4=0

1/x+1/x²=x+1/x²

2x/(x-1)(x+1)×x+1/x²=2/x²-x