x 2
------- , ----------
x^2-4 (x+2)^2
y^2 x
-------- + ------
x^2-xy y-x
x 2
------- , ----------
x^2-4 (x+2)^2
y^2 x
-------- + ------
x^2-xy y-x
1. X(X+2) 2(X-2)
----------- ------------
(X+2)(X-2)(X+2) (X+2)^2(X-2)
2. Y^2 X * (-X)
---------------- + -------------------
X(X-Y) (Y-X)*(-X)
Y^2-x^2
= -------------------
X(X-Y)
(Y-X) (Y+X)
= ----------------
X(X-Y)
X+Y
= - ---------------------
X
x/(x²-4),2/2(x+2)²
解:x/(x²-4)=x/(x+2)(x-2)= x*(x+2) / (x+2)(x-2)*(x+2)=(x²+2x) / (x-2)(x+2)²
2/(x+2)²=2/(x+2)(x+2)=2*(x-2) / (x+2)(x+2)*(x-2)=(2x-4) / (x-2)(x+2)²
y²/(x²-xy)+ x/(y-x)
解:原式=y²/x(x-y)-x/(x-y)
=y²/x(x-y)-x²/x(x-y)
=(y²-x²)/x(x-y)
=-(x²-y²)/x(x-y)
=-(x+y)(x-y)/x(x-y)
=-(x+y)/x
------- = —————— ——
x^2-4 (X-2)(X+2)^2
2 2(X-2)
—————=————————
(x+2)^2 (X-2)(X+2)^2
2、 y^2 x y^2- x^2 (y-x) (y+x) - (y+x)
-------- + ------= ———— = ——————= ————
x^2-xy y-x X(X-Y) X(X-Y) x
第1
x^2+2x 2x-4
-------------- , --------------
(x+2)^2(x-2) (x+2)^2(x-2)
第2
y^2 -x^2 -(X+Y)
原式=--------------- = ---------------
x(x-y) x
-------- + ------ = ---------- 最上面那题那个逗号是乘号?
x^2-xy y-x x-y
第一个题什么意思啊
y^2/x(x-y) - x/x-y
=(y^2-x^2)/x*(x-y)
=(y+x)(y-x)/x(x-y)
=-(y+x)/x