初中两题奥数题，别用太难的解

1.解：
x=6y/(2y+3)
原式=-5/11
2.解：
(X*X+6X+10)/(X*X+6X+9)=1+[1/(X*X+6X+9)]
(X*X-11)/(X*X-9)=1-[2/(X*X-9)]
(2X*X+8X+5)/(X*X+4X+3)=2-[1/(X*X+4X+3)]
原式=[1/(X*X+6X+9)]-[2/(X*X-9)]+[1/(X*X+4X+3)]
=1/(X+3)*{[1/(X+3)]-[2/(X-3)]+[1/(X+1)]}
=-(10X+18)/(X^4+4X^3-6X^2-36X-27)

X^4代表X的四次方

1.解：
x=6y/(2y+3)
原式=-5/11
2.解：
(X*X+6X+10)/(X*X+6X+9)=1+[1/(X*X+6X+9)]
(X*X-11)/(X*X-9)=1-[2/(X*X-9)]
(2X*X+8X+5)/(X*X+4X+3)=2-[1/(X*X+4X+3)]
原式=[1/(X*X+6X+9)]-[2/(X*X-9)]+[1/(X*X+4X+3)]
=1/(X+3)*{[1/(X+3)]-[2/(X-3)]+[1/(X+1)]}
=-(10X+18)/(X^4+4X^3-6X^2-36X-27)

X^4代表X的四次方

1. 1/x -1/2y =1/3 则， (2y-x)/2xy=1/3
3(2y-x)=2xy 3xy= 9y-4.5x
算式转化为 (2x + 9y-4.5x-4y)/(x-9y+4.5x-2y)
即 (5y-2.5x)/(5.5x-11y)=2.5(2y-x)/5.5(x-2y)= -5/11

2. 此类题，显然不论x的取值，结果都是确定的。不妨令x=0 代入，结果为5/9
也可以先通分，然后合并同类项，结果一样

1.1/xy(2x+3xy-4y)/[1/xy(x-3xy-2y)]
=.(2/y+3-4/x)/