Bonjour,
Developper :
(a + b)² = a² + 2ab + b²
(a - b)² = a² - 2ab + b²
A = (x + 9)²
A = x² + 18x + 81
B = (y - 3)²
B = y² - 6y + 9
C = (5 - 2t)²
C = 25 - 20t + 4t²
D = (x - 1,5)²
D = x² - 3x + 2,25
E = (9x + 9)²
E = 81x² + 162x + 81
F = (1,5p - 2,5)²
F = 2,25p - 7,5p + 6,25