Réponses

2012-09-10T18:09:26+02:00

4(1/2y-1)(1/2y/1)=4(1/4y²+2y-2y-1)=4(1/4y²-1)=4/4y²-1

2012-09-10T18:14:49+02:00

  4(1/2 y-1)(1/2 y+1 )

=(4^1/2 y ) -(4^1) (1/2 y+1)

=(2y -4 ) (1/2 y+1)

=2y^1/2 y +2y ^1 -4^1/2 y -4^1

=1y² +2y -2y -4

=1y²-4