d) 3 x - 6 x² = 0
3 x ( 1 - 2 x) = 0
soit 3 x = 0 et x = 0
soit 1 - 2 x = 0 donc - 2 x = - 1 et x = 1/2
e) 4 x² - 49 = 0
( 2 x - 7) ( 2 x + 7) = 0
soit 2 x - 7 = 0 donc 2 x = 7 et x = 7/2
soit 2 x + 7 = 0 et x = - 7/2
3 x ( 5 x - 2) = 10 x - 4
15 x² - 6 x = 10 x - 4
15 x² - 6 x - 10 x + 4 = 0
15 x² - 16 x² + 4 = 0
- x² = - 4
- x = - 2
x = 2
