Réponses

2013-04-02T21:27:32+02:00

f(x) = (2x+1)(x-3) + (2x+1)(3x+2)

= 2x^2-6x+x-3 + 6x^2+4x+3x+2

=8x^2+2x-1

 

f(x) = (2x+1)(x-3) + (2x+1)(3x+2)

= (2x+1)(x-3+3x+2)

= (2x+1)(4x-1)

 

f(0) = -1

f(-1/2) = 0

f(V2) = 8*(V2)^2+2V2-1 = 16+2V2-1 = 2v2+15

 

f(x) = 0

donc (2x+1)(4x-1) = 0

donc 2x+1=0ou 4x-1=0

donc x=-1/2 ou x=1/4

 

f(x)=8x^2

donc  8x^2+2x-1 = 8x^2

donc 2x-1=0

donc x=1/2

 

voila, bon courage....