Question

[Aya aya]

Tìm x,y thuộc N biết 

x.y=8

(x—2).(y+3)=15

Answer 1

[Nguyễn Phương Uyên]

\(x\cdot y=8\)

\(\Rightarrow x;y\inƯ\left(8\right)\)

\(\Rightarrow x;y\in\left\{-1;1;-2;2;-4;4;-8;8\right\}\)

\(\left(x-2\right)\left(y+3\right)=15\)

\(\Rightarrow\left(x-2\right);\left(y+3\right)\inƯ\left(15\right)\)

\(\Rightarrow\left(x-2\right);\left(y+3\right)\in\left\{-1;1;-3;3;-5;5-15;15\right\}\)

ta có bảng :

x-2	-1	1	-3	3	-5	5	-15	15
y+3	-15	15	-5	5	-3	3	-1	1
x	1	3	-1	5	-3	7	-13	17
y	-18	12	-8	2	-6	0	-4	-2