Réponse :
A = ( x + 2) (3x − 1)
A = x * 3x - x + 2 * 3x - 2
A = 3x² - x + 6x - 2
A = 3x² + 5x - 2
B = ( 3 x − 5 )²
B = (3x)² - 2 * 3x * 5 + 5²
B = 9x² - 30x + 25
C = (x + 7) ²
C = x² + 2x * 7 + 7²
C = x² + 14x + 49
D = ( 5x + 2) (5x − 2)
D = (5x)² - 2²
D = 25x² - 4