bonsoir
a = ( 3 + √2)² = 9 + 6 √2 + 2 = 11 + 6 √2
b = ( 5√3 + 2)² = 75 + 20√3 + 4 = 79 + 20√3
c = ( √27 - 6)² = 27 - 12 √27 + 36 = 63 -12 √27 = 63 - 36√3 = 36√3
d = ( 2 x + 3)² - ( 5 x - 4)² = ( 2 x + 3 + 5 x - 4 ) ( 2 x + 3 - 5 x + 4)
= ( 7 x - 1) ( - 3 x + 7)