Question

Aflaţi nr nat x şi y , ştiind că (x-3)×(y+4)=12

Answer 1

$\it y\in\mathbb{N} \Rightarrow y+4\geq4 \\ \\ (x-3)\cdot(y+4)=12 =1\cdot12=2\cdot6=3\cdot4\Rightarrow \\ \\ x-3\in\{1,2,3\}|_{+3}\Rightarrow x\in\{4,5,6\}\\ \\ y+4\in\{12,6,4\}|_{-4}\Rightarrow y\in\{8,2,0\}$

$\it (x,y)\in\{(4,8),\ (5,2),\ (6,0)\}$