Réponses

2013-04-29T21:14:39+02:00

A=(2x-3)(x+4)-3x²

= (2x²+8x-3x-12)-3x²

= 2x²+8x-3x-12-3x²

=-x²+5x-12

 

B=(3x-5)(3x-5)

= 9x²-15x-15x+25

=9x²-30x+25

 

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

= 9x²+15x-15x-25

=9x²-25

 

D=x/2+3

= x/2+6/2

=(x+6)/2