Răspuns :
x=ℕ {2,3...9} diferit de 0
y=ℕ {0,1,2,3...9}
Caz 1 :
(2-1)×(0+4)=1×4=4 (Fals)
Caz 2:
(3-1)×(4+4)=2×8=16 (Fals)
Caz 3:
(3-1)×(5+4)=2×9=18 (Fals)
Caz 4:
(6-1)×(0+4)=5×4=20 (Adevarat)
x=6 , y=0
x=ℕ {2,3...9} diferit de 0
y=ℕ {0,1,2,3...9}
Caz 1 :
(2-1)×(0+4)=1×4=4 (Fals)
Caz 2:
(3-1)×(4+4)=2×8=16 (Fals)
Caz 3:
(3-1)×(5+4)=2×9=18 (Fals)
Caz 4:
(6-1)×(0+4)=5×4=20 (Adevarat)
x=6 , y=0