Réponses

2014-02-28T20:47:35+01:00
1) 24x - 6x - 48 + 12 x = 0
30x= 48
X = 48/30 = 16/3

2) 3x -48+12x=0
15x= 48
X= 48/15=16/5
3) 45x= 21
X= 21/45= 7/15
4) 25- x^2 + 6x + 9=0
2014-02-28T20:59:47+01:00
(3x - 6) (8 - 2x) = 0

Soit

3x - 6 = 0 
3x = 6
x = 6/3 = 2
Ou

8 - 2x = 0
- 2x = - 8
2x = 8
x = 8/2 =  4

Donc , la solution 2   et   4


3x - 6 (8 - 2x) = 0
3x - 48 - 12x = 0
-9x = 48
x = - 48/9 = - 16/3


5x 7
 3     9
5x * 9 = 7 * 3
45x = 21
x = 21/45 =  7/15