若x=2^2009,y=(-2)^2009.则4x^2-8xy+4y^2=

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 若f(x+y,y/x)=x^2-y^2,则F(X,Y)= 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 若x*x+y*y=x+y-1/2,求x,y的值如题 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 若2x=3y,则(x*x+y*y)/x*x=? 已知x=3分之一,y=-2分之一,求代数式x-(x+y)+(x+2Y)-(x+3y)+(x+4y)...-(x+2009y) 若集合A={(x,y)|y>=|x-2|} ,B={(x,y)|y 化简(x^2-y^2)/(x+y)解法一：(x^2-y^2)/(x+y)=(x+y)(x-y)/(x+y)=x-y解法二：(x^2-y^2)/(x+y)=(x^2-y^2)(x-y)/(x+y)(x-y)=(x^2-y^2)(x-y)/(x^2-y^2)=x-y你认为小红同学的两种解法对吗?若解法错误,请说明原因 填空：x-y/x+y=( )/x^2-y^2 先化简,再求值 （1）[(x-y)的平方+（x+y)(x-y)]÷2x 其中X=2010,y=2009 （2)y(x+y)+(x+y)(x-y)-x的平方,先化简，再求值（1）[(x-y)的平方+（x+y)(x-y)]÷2x 其中X=2010,y=2009（2)y(x+y)+(x+y)(x-y)-x的平方,其中x=-2,y=二分 （x-y)2•(y-x)³(x-y)=? 若变量x,y满足约束条件{x>=-1;y>=x;3x+2y 若x,y,z成等差数列,则(z-x)^2-4(x-y)(y-x)= 若3x-5y=0,则x+y/x=（）,x-y/y=（）,2x-3y/2x+3y=( ) y+y'-2y=2x 若|x+y-1|+（x-y-2)²=0,求代数式（x+2y)(x-2y）-（2x-y)(-y-2x)的值.