Question

Tìm nhiệm nguyên

2x-xy+4x-2y=4

Answer 1

\(6x-xy-2y=4\)

\(\Leftrightarrow x\left(6-y\right)+2\left(6-y\right)=16\)

\(\Leftrightarrow\left(6-y\right)\left(x+2\right)=16\)

\(\Leftrightarrow6-y=\frac{16}{x+2}\)

\(\Leftrightarrow6-\frac{16}{x+2}=y\)( x khác -2)

Vì x,y nguyên nên để y nguyên thì \(x+2\inƯ\left(16\right)=\left\{\pm1;2;\pm4;\pm8;\pm16\right\}\)

x+2	x	y
1	-1	-10
-1	-3	22
2	0	-2
4	2	2
-4	-6	10
8	6	4
-8	-10	8
16	14	5
-16	-18	7

Kết luận:......