1
1)1/(x-1)-3/9x-1)9x²+x=1)-1/9x²+x+1)=(x²+x+1-3-x+1)/(x-1)9x²=x=10=
=(x²-1)/9x-1)9x²+x+1)=(x-1)(x+1)/9x-1)(x²+x=1)=(x+1)/(x+x+1)=(x+1)/(x²+x+1)
2)(x+1)/9x²+x+1) * (x²+x+1)=x+1
x=99 99+1=100
2
1)y/x-x/y=(y²-x²)/xy
2)2-x/y-y/x=(2xy-x²-y²)/xy=-(x²-2xy+y²)/xy=-(x-y)²/xy
3)(y²-x²)/xy:[-(x-y)²/xy]=(x-y)(x+y)/xy*xy/(x-y)²=(x+y)/(x-y)
x=99;y=-1 (99-1)/(99+1)=98/100=0,98
3
1)(x+y)/(x²+xy+y²)-1/(x-y)+[(x+y)²+2y²]/(x-y)(x²+xy+y²)=
=(x²-y²-x²-xy-y²+x²+2xy+y²+2y²)/(x-y)(x²+xy+y²)=(x²+xy+y²)/(x-y)(x²+xy+y²)=
=1/(x-y)
2)1/y-1/x=(x-y)/xy
3)1/(x-y)*(x-y)/xy=1/xy
x=2;y=5 1/(5*2)=0,1