Réponses

2014-05-05T15:29:01+02:00
4x(5-2y) = 4x(5) + 4x (-2y) =20x - 8xy
(6 + 2a) 3 = 3(6) + 3 (2a) = 18 +6a
2y ( x + 3y) = 2y(x) + 2y (3y) = 2xy + 6y²
3x (5-4x) = 3x(5) + 3x (-4x) =15x - 12x²
4a (2a + 3b) = 4a(2a) + 4a(3b) = 8a² +12ab
9(5x-2z) =9(5x) + 9(-2z) = 45x - 18z

2) nbre choisi :12 
12+8=20
20x3=60
60-24=36
36-36=0
nbre choisi :14 
14+8=22
22x3=66
66-24=42
42-42=0
(x+8)3-24-3x =
3x+24-24-3x = 0