Răspunsuri

2014-10-28T17:48:46+02:00
(x-1)(2-y)=-1 
2x-xy-2+y=-1
2x-xy+y-2+1=0
2x-xy+y-1=0  
2x-xy+y=1
x-xy+y+x=1
x(1-y)+y+x=1