如果x+y=3,x^2+y^2=6,x^4-y^4=24,那么x-y=?

如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y, 如果A={（x,y）|x,y+2>0},B={（x,y）|2x+3y-6>0},C={（x,y）|x-4 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 x.y是非零实数,如果2x-y/3y=y/x,那么x/y= 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 如果|X|=4 |Y|=2 且|X+Y|=X+Y 求X+Y x+y/2+x-y/6=5 2(x+y)-3(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+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 2(x+y)-3(x-y)=1 6(x+y)+(x-y)=51 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 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 如果x+y/2=x-y/3=3x-2y+9/4,那么x= ,y=如果x+y/2=x-y/3=3x-2y+9/4,那么x= ,y= 如果x+y=3,x-y=2,则x^2-y^2