bonjour
4.3 x + 12 = 33 - 5.7 x
4.3 x + 5.7 x = 33 - 12
10 x = 21
x = 21/10 = 2.1
3 x - 2 x + 8 = 5 + 4 - 8 x
x + 8 x = 9 - 8
9 x = 1
x = 1 /9
( 3 x + 7 ) ( 4 x - 8 ) = 0
un des facteurs = 0
soit 3 x + 7 = 0 et x = - 7 /3
soit 4 x - 8 = 0 et x = 8/4 = 2
( 9 x - 4 ) ( - 2 + 5 x ) - 9 x - 4 ) ( 3 x - 5 ) = 0
on factorise
( 9 x - 4 ) ( - 2 x + 5 - 3 x + 5 ) = 0
( 9 x - 4 ) ( - 5 x + 10 ) = 0
x = 4/9 = 2/3
ou x = 10 /5 = 2
8 + 2 x² = 40
2 x² = 40 - 8
2 x² = 32
x² = 16
x = √16 ou - √16
x = 4 ou - 4
9 x² - 36 = 0
identité
( 3 x - 6 ) ( 3 x + 6 ) = 0
x = 6/3 = 2
ou x = - 6/3 = - 2
bonne journée
