Question

tim x va y thuoc z

   /x-1/+/y+1/=0

Answer 1

|x-1|+|y+1|=0

ta có:|x-1|>0;|y+1|>0

=>|x-1|+|y+1|>0

theo đề:|x-1|+|y+1|=0

=>x-1=y+1=0

=>x=1;y=-1