Explicație pas cu pas:
a+b= 56
(a, b)=4 => a=4x
b=4y
(x, y)=1
4x+4y= 56
4(x+y)= 56
x+y= 14
x 1 3 5 9 11 13
_____________________________ => (inmultim cu 4)
y 13 11 9 5 3 1
=> a 4 12 20 36 44 52
___________________________________
b 52 44 36 20 12 4
(a, b)= {(4, 52), (12, 44), (20, 36), (36, 20), (44, 12), (52, 4)}
Am rezolvat sub forma de tabel daca nu intelegi :)