Question

[Bạch Nguyễn Hưng Nguyên]

Tìm số nguyên x,y thoả mãn: xy - 2x - y = 2

Answer 1

[14456125]

\(xy-2x-y=2\\ \text{X}\left(y-2\right)-y=2\\ \text{X}\left(y-2\right)-\left(y-2\right)=2+2=4\\ \left(x-1\right)\left(y-2\right)=4\\ \Rightarrow y-2\in\text{Ư}\left(4\right)=\left\{\pm4;\pm2;\pm1\right\}\)

Lập bảng 

y-2	-4	-2	-1	1	2	4
y	-2	0	1	3	4	6
x-1	-1	-2	-4	4	2	1
x	0	-1	-3	5	3	2