Réponses

Meilleure réponse !
2014-10-28T16:11:29+01:00
A = (x + 3)² = x² + 2.x.3 + 3² = x² + 6x + 9
B = (2x + 1)(x - 4) = 2x.x - 2x.4 + 1.x -1.4 = 2x² - 8x + x - 4 = 2x² - 7x - 4
C = (x + 1)² - (x-2)² = ((x + 1) - (x - 2))((x + 1) + (x - 2))
C = (x + 1 - x + 2)(x + 1 + x - 2) = (3)(2x - 1) = 6x - 3
D = (x + 1)² + (1 - 2x)² = ( x² + 2x + 1) + (1 - 4x + 4x²)
D = x² + 2x + 1 + 1 - 4x + 4x²  
D = 5x² - 2x + 2