Bonjour, aidez-moi pour les 4 exercices de maths svp, c'est un devoir maison. Aidez-moi SVP.
Question
2 Réponse
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1. Réponse Vins
bonjour
7 x - x - 2 = x - 3
6 x - x = - 3 + 2
5 x = - 1
x = - 1/5
1 - ( 3 x - 1 )/ 5 = 0
5/5 - ( 3 x - 1 ) /5 = 0
- 3 x + 1 = - 5
- 3 x = - 5 - 1
- 3 x = - 6
x = 2
(4 x + 3 ) / 5 = ( 2 x - 1 ) 6
24 x + 18 = 10 x - 5
24 x - 10 x = - 5 - 18
14 x = - 23
x = - 23/14
( 3 x + 9 ) ( 4 x - 2 ) = 0
un des facteurs est nul
soit 3 x + 9 = 0 et x = - 9/3 = - 3
soit 4 x - 2 = 0 et x = 2/4 = 1/2
30 x² + 10 x = 0
10 x ( 3 x + 1 ) 0
soit 10 x = 0 et x = 0
soit 3 x + 1 = 0 et x = - 1/3
( 5 x + 1 ) ( 3 - 2 x ) = 0
soit 5 x + 1 = 0 et x = - 1/5
soit 3 - 2 x = 0 et x = 3/2
continue
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2. Réponse maudmarine
Bonjour,
115)
a. 7x - (x + 2) = x - 3
7x - x - 2 = x - 3
7x - x - x = - 3 + 2
5x = - 1
x = - 1/5
b. 1 - (3x - 1) / 5 = 0
5/5 - (3x - 1) / 5 = 0
3x + 1 + 5 = 0
3x = - 5 - 1
3x = - 6
x = - 6/3
x = - 2
116)
a. (4x + 3) / 5 = (2x - 1) / 6
(24x + 18) / 30 = (10x - 5) / 30
24x + 18 = 10x - 5
24x - 10x = - 5 - 18
14x = - 23
x = - 23/14
b. 5/6 - (3x + 4) / 4 = x
20/24 - (18x + 24) / 24 = 24/24x
20 - 18x - 24 = 24x
- 18x - 24x = 24 - 20
- 42x = 14
x = - 14/42
x = - 1/3
117)
a. (3x + 9) (4x - 2) = 0
3x + 9 = 0 ou 4x - 2 = 0
3x = - 9 4x = 2
x = - 9/3 x = 2/4
x = - 3 x = 1/2
b. (5x + 1) (3 - 2x) = 0
5x + 1 = 0 ou 3 - 2x = 0
5x = - 1 - 2x = - 3
x = - 1/5 x = 3/2
118)
a. 5x (6x + 2) = 0
5x = 0 ou 6x + 2 = 0
x = 0 6x = - 2
x = - 2/6
x = - 1/3
b. (1/7x + 2) (1 - x) = 0
1/7x + 2 = 0 ou 1 - x = 0
1/7x = - 2 - x = - 1
x = - 2 : 1/7 x = 1
x = - 2 * 7
x = - 14.