xy=x+y
=>x+y-xy=0
=>(x-xy)+(y-1)=(-1)
=>x(1-y)+(1-y)=(-1)
=>(x+1)(1-y)=(-1)
=>y=2 thì x=2
y=0 thì x=0
\(xy=x+y\)
\(=>xy-x-y=0\)
\(=>\left(xy-x\right)-y=0\)
\(=>\left(xy-x\right)-y+1=1\)
\(=>x\left(y-1\right)-\left(y-1\right)=1\)
\(=>\left(x-1\right).\left(y-1\right)=1\)
=>
x-1 | 1 | -1 |
x | 0 | 2 |
y-1 | -1 | 1 |
y | 0 | 2 |
=>cặp giá trị (x;y)thoả mãn là : (0;0)hoặc (2;2)