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Soit A = 9sc² - 1 ( sc = x )
quelle identité remarquable permet de factorisé A ? Factoriser A
Soit B : ( 3sc + 1 )² + 9sc² - 1
develloper B
factorisé B
determiné les solutiosn a l'equation 6sc(3sc+1)=0

2

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2014-10-30T12:08:15+01:00
A = 9x²-1

identite remarquable (a-b)(a+b)
donc(3x-1)(3x+1)

b =(3x+1)²-(9x²-1)
b =9x²+6x+1-9x²+1
b = 6x+2

factoriser
b= (3x+1²) -(3x-1)(3x+1)
b =(3x+1)(3x+1-3x+1)
b= (3x+1)(2)
b =2(3x+1)

6x(3x+1) = 0

6x =0                        3x+1 =0
x = 0                         3x = -1
x =0                            x = -1/3
2014-10-30T12:09:04+01:00
Bonjour

A = 9 x² - 1
    = ( 3 x -1)(3 x +1)

B = ( 3 x +1 )² + 9 x² -1
   = 9 x² + 6 x + 1 + 9 x² - 1
   = 6 x

B = ( 3 x + 1)²  + ( ( 3 x + 1)( 3 x -1)
    ( 3 x +1 )( 3 x +1 + 3 x -1)
  = ( 3 x +1) ( 6 x )

6 x ( 3 x +1) = 0
soit  6 x = 0 et x = 0
soit 3 x +1 = 0
3 x = - 1
x = -1/3