Question

tim x,y thuoc Z:xy+2x-y=9

Answer 1

xy + 2x - y = 9

<=> xy + 2x - y - 2 = 7

<=> x(y + 2) - (y + 2) = 7

<=> (x - 1)(y + 2) = 7

x - 1	1	-1	7	-7
y + 2	7	-7	1	-1
x	2	0	8	-6
y	5	-9	-1	-3

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