bonsoir
a) 15 x - 30 x² - 4 x = - 30 x² + 11 x
b) 15 x - 12 x² - 10 + 8 x - 21 x + 6 = - 12 x² + 2 x - 4
c) 5 x² - 12 + 28 x
d) 20 x - 5 - ( - 10 x² - 14 x - 15 x - 21)
= 20 x - 5 + 10 x² + 14 x + 15 x + 21
= 10 x² + 49 x + 16
A = 3 x² - 6 x - x + 5
= 3 x² - 7 x + 5
bonsoir
a) 5x(3-6x)-4x = 15x - 30x² - 4x = -30x² + 11x
b) (3x-2)(5-4x)-3(7x-2)
15x - 12x² - 10 + 8x - 21x + 6 = -12x² + 2x - 4
c) 5x(au carré)-4(3-7x)
5x² - 12 + 28x = 5x² +28x - 12
D)5(4x-1)-(2x+3) (-5x-7)
20x - 5 + 10x² + 14x + 15x + 21 = 10x² +49 x + 16
:) calculs à vérifier - erreurs possibles
