Réponses

2012-05-25T18:51:20+02:00

1) A= (5x-1)²-(5x-1)(x+3)

=25x²-10x+1-(5x²+15x-x-3)

=25x²-10x+1-5x²-15x+x+3

=20x²-24x+4

 

2) A=(5x-1)²-(5x-1)(x+3)

=(5x-1)(5x-1)-(5x-1)(x+3)

=(5x-1)(5x-1-x-3)

=(5x-1)(4x-4)

2012-05-25T20:16:15+02:00

A= ((5x)²-2*5x*1+1²)-(5x*x+5x*3-1*x-x*3)

  =(25x²-10x+1)-(5x²+15x-x-3)

   =(25x²-10x+1)-(5x²+14x-3)

   = 25x²-10x+1-5x²-14x+3

    =20x²-24x+5

B= x(20x-24)+5