Réponses

2014-03-08T20:52:34+01:00
A) (2x-4)(x-3 - 5x +8)
 = (2x-4)(-4x +5)

b) 25x² -20x +4 = (5x -2)²

c) 81 -9x² = (9 -3x)(9 +3x)