Question

Aflati numerele naturale x si y stiind ca x*y+5*y=20.

Answer 1

Dai y factor comun:
y*(x+5)=20
!. y=20 => x+5=1, x=-4
!!. y=10 => x+5=2, x=-3
III. y=5 => x+5=4, x=-1
IV. y=4 => x+5=5, x=0
V. y=2 => x+5=10, x=5
VI. y=1 => x+5=20, x=15

(x,y) ∈ {(0,4),(5,2),(15,1)}