Sagot :
bonjour
x = √5 - 2 et y = √5 + 2
x² = ( √5 - 2 )²
x² = 5 - 4 √5 + 4
x² = 9 - 4 √5
y ² = ( √5 + 2 )²
y² = 5 + 4 √5 + 4
y ² = 9 + 4 √5
xy = ( √5 - 2 ) ( √5 + 2) = 5 - 4 = 1
bonjour
x = √5 - 2 et y = √5 + 2
x² = ( √5 - 2 )²
x² = 5 - 4 √5 + 4
x² = 9 - 4 √5
y ² = ( √5 + 2 )²
y² = 5 + 4 √5 + 4
y ² = 9 + 4 √5
xy = ( √5 - 2 ) ( √5 + 2) = 5 - 4 = 1