Réponses

2013-09-04T23:12:10+02:00
A=x(2x-1)-5(2x-1)(x+3)
  =(2x-1)[x-5(x+3)]
 =(2x-1)(x-5x-15)
 =(2x-1)(-4x-15)
B= (x+3)au carré-(2x+1)au carré
  =[(x+3)+(2x+1)][(x+3)-(2x+1)]
 =(x+3+2x+1)(x+3-2x-1)
=(3x+4)(-x+2)
C= 4xau carré-(x-3)au carré
  =[2x+(x-3)][2x-(x-3)]
  =(2x+x-3)(2x-x+3)
  =(3x-3)(x+3)