x^2-y^2=(x+4)(7-y),则x^y-2=

若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 (x-y)(x-2y)+(x-2y)(x-7y),其中X=4,Y=1.5 已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? x^2-y^2=(x+4)(7-y),则x^y-2= 已知|5x-y-8|+(7y-x+2)=0则4x+6y (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (x-4y)(2x+y)= 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 若x,y,z成等差数列,则(z-x)^2-4(x-y)(y-x)= 设2x-y/x+y=3,其中x,y≠0则[（2x-3y)^3-(3x-2y)^3]/[(4x+2y)^3-(x-7y)^3]=? 2x-y/x+y=4,则4x-2y/2x+2y+3x+3y/2x-y 已知方程组{(X+Y)-3(X-Y)=7,2(X+Y)+(X-Y）=-7}则(X+Y)(X-Y)= 已知（x+y）2 =2,(x-y)3 =3,求(x+y)7(x-y)2(x+y)3(y-x)4 的值 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（） 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 4x方y/(x-2y)(x+2y)怎么算[x方/x-2y]-4x方y/(x-2y)(x+2y)=? 把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)= 3(x-y)把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)=3(x-y)²-4(x-y)+7(x-y)-6(x-y)²=