$\frac{3-x}{4}$ = $\frac{3}{1+y}$ ⇒ ( 3-x )( 1+y )=3.4 ⇒ ( 3-x )( 1+y ) = 12
Do x,y ∈ Z nên 3-x, 1+y ∈ Ư(12)
Ta có: 12 = 1.12 = (-1).(-12)=3.4=(-3).(-4)=2.6=(-2).(-6)
Ta có bảng sau:
3-x 1 12 -1 -12 3 4 -3 -4 2 6 -2 -6
1+y 12 1 -12 -1 4 3 -4 -3 6 3 -6 -2
X 2 -9 4 15 0 -1 6 -7 1 -3 5 9
Y 1 10 -13 -2 3 2 -5 -4 5 2 -7 -3
Vậy (x,y) ∈ {(2,1),(-9,10),(4,-13),(15,-2),(0,3),(-1,2)(6,-5),(-7,-4),(1,5),(-3,2),(5,-7),(9,-3)}
