y=2x^2-4x-8 y=0.5x^2+2x-1

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= (x-4y)(2x+y)= 4x方y/(x-2y)(x+2y)怎么算[x方/x-2y]-4x方y/(x-2y)(x+2y)=? 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= [(2x-y)^2-y(y-4x)-8x]其中x=-1/2 y=2x^2-4x-8 y=0.5x^2+2x-1 9y=3x-(x-1),4(x+y)-(2x+4)=8y [(2x+y)²-y(y+4x)-8x】/4x,其中x=-1,y=2005 急 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 若x-y=1 化简（x+y)(x^2+y^2)(x^4+y^4)(x^8+y^8)(x^16+y^16) 已知实数x.y满足根号(x+y-8)+根号(8-x-y)=根号(3x-y-4)+根号(x-2y+7),求x,y (x+y)^2(x-y)^2(x^4+x^2y^2+y^4)=? 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 （x+y）/2- x-y/2=6 3(x+y)=4(x-y) x+y/3+x-y/2=6 4(x+y)-2(x-y)=40 x*x+2x+y*y-4y+5=0 x= y=