Réponse :
Il faut que tu utilise la formule (a+b)² = a²+ 2 × a × b + b²
A = (x+1)² a = x et b = 1 B = (2x+3)² a = 2x et b = 3
A = x² + 2 × x × 1 + 1² B = 2x² + 2 × 2x × 3 + 3²
A = x² + 2x + 1 B = 4x² + 12x + 9
C = (5x+1)² a = 5x et b = 1 D = (x+6)² a = x et b = 6
C = 5x² + 2 × 5x × 1 + 1² D = x² + 2 × x × 6 + 6²
C = 25x² + 10x + 1 D = x² + 12x +36
