x^2-y^2=8,x-y=4,则x+y的结果是...:如题

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= [(x+2y)(x-2y)-(x-2y)^2+8y(x+y)]除以4x= 已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? (x-4y)(2x+y)= 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 若X+Y=8,(X-Y)^2=4,则X^2+Y^2= x+5y+2=0,则4^2x+y*8^y-x 已知|5x-y-8|+(7y-x+2)=0则4x+6y (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 4x方y/(x-2y)(x+2y)怎么算[x方/x-2y]-4x方y/(x-2y)(x+2y)=? 9y=3x-(x-1),4(x+y)-(2x+4)=8y [(2x-y)^2-y(y-4x)-8x]其中x=-1/2 若x,y,z成等差数列,则(z-x)^2-4(x-y)(y-x)= 2x-y/x+y=4,则4x-2y/2x+2y+3x+3y/2x-y 若x-y=1 化简（x+y)(x^2+y^2)(x^4+y^4)(x^8+y^8)(x^16+y^16) 若x+y=4,则多项式1/2(x+y)+4(x-y)-3（x-y）-3/2(x+y)-x+y值是（） [(2x+y)²-y(y+4x)-8x】/4x,其中x=-1,y=2005 急