2x+y/5=3x-2y/8=2

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-2y=9 x-3y=2 x+y=5 x+2y=3 y=x 2x+y=8 x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x 12y(x-y)^2-8(x-y)^3=? x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 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 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5 {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? {x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (x+y)(x-y)+(x-y)平方-(x-y)(3x-y) 其中x=-2 y=3分之一