=>x^2-y^2-xy-y^2=1
=>(x-y)(x+y)-y(x+y)=1
=>(x+y)*(x-2y)=1
=>(x+y;x-2y)=(1;1) hoặc (x+y;x-2y)=(-1;-1)
=>(x,y)=(1;0) hoặc (x,y)=(-1;0)
tim cac so nguyen x, y thoa man x>y>1 va 2x + 2y + 1 chia het cho xy
tim cac so x,y thoa man :2x^2+y^2-2y=2(xy-1)
tim cac gia tri x y thoa man
a,(x^2-1)(x^2-16)<0 va x thuoc Z
B,1/x-y/8=1/16 va x y thuoc N
tim cap so nguyen (x, y)thoa man 2y2= 5-/x-1/
cho cac so x,y,z va x+y+z khac 0 thoa man dieu kien
\(\frac{x+2y}{x+2y-z}+\frac{y+2z}{y+2z-x}+\frac{z+2x}{z+2x-+y}\)
tinh gt bieu thuc \(T=\frac{x^2+y^2}{xy}+\frac{y^2+z^2}{yz}+\frac{z^2+x^2}{zx}\)
tim cap so nguyen (x,y) thoa man: x+y+xy=2
Biet x;y;z thoa man x-1/2=y-2/3=x-3/4 va x-2y+3x=-10. Khi do x+y+z =?
cho x,y thoa man :x-2/2=y-3/3 va x+y=10 khi do xy=
tim x,y thuoc z thoa x^2+xy+y^2=x^2y^2
