bonjour,
A = ( 3 x - 2 )² - 9
1. A = 9 x² - 12 x + 4 - 9 = 9 x² - 12 x - 5
2. A = ( 3 x - 2 - 3 ) ( 3 x - 2 + 3 ) = ( - 3 x - 5 ) ( 3 x + 1 )
3. pour x = √2
A = ( - 3 √2 - 5 ) ( 3 √2 + 1 ) = - 9 √4 - 3 √2 - 15 √2 - 5 = - 18 - 5 - 18 √2
= - 23 - 18 √2
A = 0
( - 3 x - 5 ) ( 3 x + 1) = 0
x = - 5/3 ou - 1/3
A = 16
( 3 x - 2 )² - 9 = 16
( 3 x - 2)² - 9 - 16 = 0
( 3 x - 2 )² - 25 = 0
( 3 x - 2 - 5 ) ( 3 x - 2 + 5 ) = 0
( 3 x - 7 ) ( 3 x + 3 ) = 0
x = 7/3 ou - 1
a. x² - 5 x = 0
x ( x - 5 ) = 0
x = 0 ou 5
- 3 x² + x = 0
x ( - 3 x + 1 ) = 0
x = 0 ou 1/3
4 x² = 28 x
4 x² - 28 x = 0
4 x ( x - 7 ) = 0
x = 0 ou 7