tim x, y thuoc z biet :
/ x-y / + / y-z/ + /z - x / = 2015
tim x,y,z thuoc z biet /x/+/y/+/z/=0
tim x,y thuoc Z biet xy=x-y
tim x ,y thuoc z biet: (x-1)(x+y) =32
tim x, y thuoc Z biet x+y -x.y = 7
tim x,y biet x,y thuoc z voi x,y cung dau x+y+|y|=2015
Tim x, y thuoc Z biet : | x-2| + (x-y+1)^2 =0
tim x,y thuoc z biet: x - y = 6 - 2xy
tim x,y thuoc z biet: x - y = 6 - 2xy