Question

Tìm số cặp số nguyên x y thỏa mãn (2x-5)(y-7)=17

Answer 1

\(\Rightarrow2x-5=17\)

      \(y-7=17\)

\(\Rightarrow2x=17+5\) 

      \(y=17+7\)

\(\Rightarrow2x=22\)

      \(y=24\)

\(\Rightarrow x=22:2\)

     \(y=24\)

\(\Rightarrow x=11\)

     \(y=24\)

Answer 2

=> 2x -5 \(\in\) Ư(17) = {1;-1;17;-17}

Ta có bảng sau:

2x-5	1	-1	17	-17
2x	6	4	22	-12
x	3	2	11	-6
y-7	17	-17	1	-1
y	24	-10	8	6

Vậy (x;y) = (3;24); (2;-10); (11;8); (-6;6)