bonjour
a) 7 x - 5 = 11 x + 3
7 x - 11 x = 3 + 5
- 4 x = 8
x = - 2
b) 4 - x = 7 x - 7
- x - 7 x = - 7 - 4
- 8 x = - 11
x = 11/8
A = ( 3 x - 2 )²
A = 9 x² - 12 x + 4
A = 0 donc ( 3 x - 2 ) ( 3 x - 2) = 0 quand x = 2
( 3 x - 2 )² = 4
( 3 x - 2 )² - 4 = 0
( 3 x - 2 - 2 ) ( 3 x - 2 + 2 ) = 0
( 3 x - 4 ) ( 3 x ) = 0 donc x = 4/3 ou 0
B = x² - 49
B = ( x - 7 ) ( x + 7)
B = 0 pour x = 7 ou - 7
B = - 45
x² - 49 = - 45
x² = - 45 + 49
x² = 4
x² - 4 = 0
( x - 2 ) ( x + 2) = 0 quand x = 2 ou - 2
essaie de faire la C