5x-2y=7 2x=3y=8

x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 3x+5y-(x+y)=6 2(x+y)-3x=-7 3x-2y=9 x-3y=2 x+y=5 x+2y=3 y=x 2x+y=8 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 解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7 12y(x-y)^2-8(x-y)^3=? x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5)