Réponse :
bonsoir
A = 9 x² - 30 x + 25 + 4 x² + 20 x + 25
A = 13 x² - 10 x + 50
B = 21 x² - 28 x - ( x² - 6 x + 9)
B = 21 x² - 28 x - x² + 6 x - 9
B = 20 x² - 22 x - 9
D = ( 9 x + 3 )²
E = ( x - 7 )²
F = ( 9 x - 2 ) ( 9 x + 2 )
G = ( 2 x + 3 - 8 ) ( 2 x + 3 + 8 ) = ( 2 x - 5 ) ( 2 x + 11 )
5 x - 7 = - 3 x + 9
5 x + 3 x = 9 + 7
8 x = 16
x = 2
- 2 x - 8 + 12 = 5 x - 7 x + 4
- 2 x - 5 x + 7 x = 4 + 8 - 12
0 x = 0
( x + 1 ) ( - x + 4 - 5 x +3 ) = 0
( x + 1 ) ( - 6 x + 7 ) = 0
x = - 1 ou 7/6
25 x² - 4 = 0
( 5 x - 2 ) ( 5 x + 2 ) = 0
x = 2/5 ou - 2/5
Explications étape par étape
