Bonsoir,
2)
(2x-1)(x-5)+(3x+7)(x-5)
(x-5)(2x-1+3x+7)
(x-5)(5x+6)
(2x+5)(x-3) - (2x+5)( -3x+1)
(2x+5)( x-3 - (-3x+1))
(2x+5)(x-3 +3x - 1)
(2x+5)(4x -4)
C = 9x²+30x+25 = (3x + 5)² identité remarquable (a + b)² = a² + b² + 2ab
D = x²+8x+16 = (x+4)²
E = x²-2x+1 = (x-1)² identité remarquable (a - b)² = a² + b² - 2ab
F = 9+4x² -12x = (3 - 2x)²
G = x² - 49 = x² - 7² = (x+7)(x-7) identité remarquable a² - b² = (a+b)(a-b)
H = 81 - x² = 9² - x² = (9+x)(9-x)
Bonne soirée
