<< Forum maths || En bas
Message de djedje31 posté le 11-03-2010 à 09:18:13 (S | E | F)
bonjour
en vérifiant je pense avoir les 2 premiers juste mais ne trouve pas mes erreurs aux autres. Merci de votre aide
a) 2x + 5x – 4 = 3x + 2 + 3x
7x - 4 = 6x + 2
7x - 6x = 2 + 4
x = 6
b) 2(x + 4) = - (x +4)
2x + 8 = -x - 4
2x + x = -4 - 8
3x = -11
x = -11/-3
c) 3(x + 3) – 2(x – 1) = x + 11
3x + 9 - 2x - 2 = x + 11
x + 7 = x + 11
x = 4
d) (x – 1) / 3 – (x +2 )/ 2 = (-3x – 2) / 6
x/3 - 1/3 - x/2 + 2/2 = -3x/6 - 2/6
x/3 - x/2 - 3x/6 = - 2/6 + 1/3 - 2/2
6x-3x-3x / 6 = - 2+2-6 / 6
x/6 = - 2/6
x = -2
e) 8x – 64(x + 2) = -56 – 24x
8x - 64x + 128 = -56 - 24x
56x + 24x = -184
x =-184/-80
x = -23/-10
2(20x – 1) / 3 = 10x + 1
40x/3 -2/3 = 30x/3 + 3/3
40x/3 - 30x/3 = 3/3 + 2/3
10x/3 = 5/3
10x = 5
x = 1/2
Réponse: Equation de logon, postée le 11-03-2010 à 09:40:16 (S | E)
Attemtion aux signes
c) 3(x + 3) – 2(x – 1) = x + 11
3x + 9 - 2x + 2 = x + 11
d) (x – 1) / 3 – (x +2 )/ 2 = (-3x – 2) / 6
x/3 - 1/3 - x/2 - 2/2 = -3x/6 - 2/6
e) 8x – 64(x + 2) = -56 – 24x
8x - 64x - 128 = -56 - 24x
Réponse: Equation de djedje31, postée le 11-03-2010 à 10:11:54 (S | E)
bonjour après rectification voilà les resultats
c) 3(x + 3) – 2(x – 1) = x + 11
3x + 9 - 2x + 2 = x + 11
3x – 2x – x = 11 – 9 + 2
x = 4
d) (x – 1) / 3 – (x +2 )/ 2 = (-3x – 2) / 6
x/3 - 1/3 - x/2 - 2/2 = -3x/6 – 2/6
x/3 – x/2 – 3x/6 = 1/3 – 2/6 + 2/2
- 4x/6 = 6/6
-4x = 1
e) 8x – 64(x + 2) = -56 – 24x
8x - 64x - 128 = -56 – 24x
8x – 64x + 24x = 128 – 56
-32x = 72
x = 72/32 = 9/7
Réponse: Equation de logon, postée le 11-03-2010 à 12:00:34 (S | E)
Ça me paraît OK.
<< Forum maths