bjr
A = 6² - (5x)² = 36 - 25x² = -25x² + 36
puisque (a+b) (a-b) = a² - b²
B = (x+1) (5-x - 2(4x+3)) = (x+1) (5 - x - 8x - 6) = (x+1) (-9x-1)
C = (8x)² - 10² = (8x+10) (8x-10)
D = 36 - (1-2x)²
si x = -1
D = 36 - (1 - 2*(-1))² = 36 - (1 +2)² = 36 - 3² = 36 - 9 = 27
D = 36 - (1 - 4x + 4x²) = -4x² + 4x + 35
D = 6² - (1-2x)² = (6 + 1-2x) (6-(1-2x)) = (-2x+7) (2x + 5)
(4x-5) (18+3x) = 0
soit 4x-5=0 => x =5/4
soit 18+3x =0 => x = -6
