bjr
A(x) = (4x)² + 2*4x*1 - ((6x)² - 2*6x*11 + 11²)
= 16x² + 8x + 1 - (36x² -132x + 121)
= 16x² + 8x + 1 - 36x² + 132x - 121
= -20x² + 140x - 120
A(x) = (4x+1 + 6x-11) (4x+1 - (6x-11)) puisque a² - b² = (a+b) (a-b)
= (10x - 10) (-2x +12)
= 10(x-1)*2(-x+6)
= 20(x-1) (-x+6)
A(x) = -20x² + 140x - 120
= -20 (x² - 7x) - 12
= -20 [(x - 7/2)² - (7/2)²] - 12
= -20 [(x - 7/2)² - 49/4] - 12
= -20 (x - 7/2)² + 980/4 - 12
erreur qq part - je cherche plus tard
