faites l exercice ci dessous svp

bonjour

A = 2 + √15
A² = (2 + √15)² = 4 + 4√15 + 15 = 19 + 4√15

B = 2 - √15
B² = ( 2 -√15)² = 4 - 4√15 +15 = 11 - 4√15

AB = (2 +√5) ( 2 - √5) = 4 - 5 = - 1

identités remarquables

A = 2+√15 et B = 2-√15

A² = (2+√15)² = 4+4√15+15 = 19+4√15
B² = (2-√15)² = 4-4√15+15 = 19-4√15
AxB = (2+√15)(2-√15) = 4-2√15+2√15-15 = 4-15 = -11