Bonjour
D = 9 x²- 1
D = ( 3 x - 1 ) ( 3 x + 1 )
E = ( 3 x + 1 )² + 9 x² - 1
E = 9 x² + 6 x + 1 + 9 x² - 1
E = 18 x² + 6 x
E = 6 x ( 3 x + 1 )
6 x ( 3 x + 1 ) = 0
x = 0 ou - 1/3
Bonsoir,
1)
a) a² -b² = (a-b)(a+b)
b) (3x-1) (3x+1)
2)
a) 9x² +6x +1 + 9x² -1
= 18x² +6x
b)
6x( 3x +1)
c)
6x( 3x +1) =0
soit 6x = 0
=> x=0
soit 3x+1 = 0
3x=-1
=> x= -1/3
