Question

aflați x,y € Z daca x(y+1)=2

Answer 1

x(y+1)=2 , x,y ∈ Z

1. (-1)·(-2)=2 => x=-1; y+1=-2; y=-3

2. (-2)·(-1)=2 => x=-2; y+1=-1; y=-2

3.   1·2=2     =>  x=1;  y+1=2; y=1

4.    2·1=2    => x=2; y+1=1; y=0

(x,y) ∈{(-2, -2); (-1, -3); (1, 1); (2, 0)}

Answer 2

x·(y+1)=2 => x=-2 <=> y+1=-1 => y=-2 ;

x=-1 <=> y+1=-2 => y=-3 ;

x=1 <=> y+1=2 => y=1 ;

x=2 <=> y+1=1 => y=0 .

S={(-2;-2),(-1;-3),(1;1),(2;0)} .