bonjour
A
x
x + 3
( x + 3 )² = x² + 6 x + 9
x² + 6 x + 9 - x²
= 6 x +9
B
6 x
6 x + 9
on prend 4 = 24 + 9 = 33
on prend - 5 = - 30 + 9 = - 21
Clément a raison
6 x + 9 = 54
6 x = 54 - 9
6 x = 45
x = 45/6 = 7.5
