7 x + 5 = 2 x - 3
7 x - 2 x = - 3 - 5
5 x = - 8
x = - 8/5
4/x = 7/8
7 x = 32
x = 32/7
9 - x = 10 x + 40
- x - 10 x = 40 - 9
- 11 x = 31
x = - 31/11
(11 x + 6) ( 4 x - 9) = 0
soit 11 x + 6 = 0 donc 11 x = - 6 et x = - 6/11
soit 4 x - 9 = 0 donc 4 x = 9 et x = 9/4
( 2 x + 1 ) ( 8 x - 7) = ( 4 x + 8 ) ( 4 x - 1)
16 x² - 14 x + 8 x - 7 = 16 x² - 4 x + 32 x - 8
16 x² - 14 x + 8 x - 16 x² + 4 x - 32 x = - 8 + 7
38 x = - 1
x = - 1/38
