Question

Determinat numere întregi x si y , știind ca: xy+4x-3y=7

Answer 1

xy+4x-3y=7
x(y+4)=7+3y
x=(7+3y)/(y+4)
x intreg→
(7+3y)/(4+y) intreg→
4+y|7+3y
4+y|4+y
4+y|3(4+y)
4+y|12+3y
4+y|7+3y-12-3y
4+y|-5
4+y€{-5,-1,1,5}
y€{-9,-5,-3,1}

y=1→
x=7+3/5=2

y=-3
x=7-9/4-3=-2/1=-2

y=-5
x=7-15/4-5=-8/-1=8

y=-9
x=7-27/4-9=-20/-5=4