bonjour
A = (y + 7)²
A = y² + 14 y + 49 = identité
B = (x + 9) (11 - 3x)
= 11 x - 3 x² + 99 - 27 x
= - 3 x² - 16 x + 99
C = (5x + 3) (5x - 3) = identité
= 25 x² - 9
D = (7 - 6y)² idem
= 49 - 84 y + 36 y²
E = (2 - 4x)² - (1 - 5x) (-7 + 6x)
= 4 - 16 x + 16 x² - ( - 7 + 6 x + 35 x - 30 x² )
= 16 x² - 16 x + 4 + 7 x - 41 x + 30 x²
= 46 x² - 50x + 4
