Bonsoir,j'ai un exercice sur résoudre des équations:
Résoudre chaque équations c'est a dire trouver le resultat de x:
5x - 45=60
-5x+89
6(x-7)=11(x+8)
7x-21=49
3x-123=720
4x-6=8x-78
9(x-3)=2(6x+7)
5(4x-3)+3(2x-4)=2(12x+5)
6(x+1)-4(x-5)=3(x-7)-4(x-2)
5(3x+1)=7(x-2)-9(5-x)
3(x+1)=4(x-6)+(x+7)

2

Réponses

Meilleure réponse !
2014-03-28T17:53:10+01:00
5x - 45 = 60
5x = 45 + 60
5x = 105
x = 105/5
x = 21

-5x + 89
-5x = - 89
x = 89/5
x = 17,8

6(x - 7) = 11(x + 8)
6x - 42 = 11x + 88
6x - 11x = 42 + 88
-5x = 130
x = -130/5
x = - 26

7x - 21 = 49
7x = 21 + 49
7x = 70
x = 70/7
x = 10

3x - 123 = 720
3x = 123 + 720
3x = 843
x = 843/3
x = 281

4x - 6 = 8x - 78
4x - 8x = 6 - 78
-4x = -72
x = 72/4
x = 18

9 (x - 3) = 2(6x + 7)
9x - 27 = 12x + 14
9x - 12x = 27 + 14
-3x = 41
x = 41/3
x = 13,66

5(4x - 3) + 3(2x - 4) = 2(12x + 5)
20x - 15 + 6x - 12 = 24x + 10
20x + 6x - 24x = 15 + 12 + 10
26x - 24x = 37
2x = 37
x = 37/2
x = 18,5

6(x + 1) - 4(x - 5) = 3(x - 7) - 4(x - 2)
6x + 6 - 4x + 20 = 3x - 21 - 4x + 8
6x - 4x - 3x + 4x = - 6 - 20 - 21 + 8
10x - 7x = - 47 + 8
3x = -39
x = -39/3
x = - 13

5(3x + 1) = 7(x - 2) - 9(5 - x)
15x + 5 = 7x - 14 - 45 + 9x
15x - 7x - 9x = - 5 - 14 - 45
15x - 16x = - 64
-1x = -64
x = 64/1
x = 64

3(x + 1) = 4(x - 6) + (x + 7)

3x + 3 = 4x - 24 + x + 7
3x - 4x - x = - 3 - 24 + 7
-2x = -20
x = 20/2
x = 10

mrc bcp :)
De rien :)
mais pourrais tu m'expliquer comment tu fait pour trouver le résultat de x stp
2014-03-28T17:54:23+01:00
5x - 45=60
5x=60-45
5x=15
x=3

-5x+89  ????

6(x-7)=11(x+8)
6x-42=11x+88
-11x+6x=88+42
-5x=130
x=-26

7x-21=49
7x=49+21
7x=70
x=70/7
x=7

3x-123=720
3x=720+123
3x=843
x=843/3
x=281

4x-6=8x-78
8x-4x=78-6
4x=72
x=72/4
x=18

9(x-3)=2(6x+7)
9x-27=12x+14
12x-9x=-27-14
3x=-41
x=-41/3

5(4x-3)+3(2x-4)=2(12x+5)
20x-15+6x-12=24x+10
26x-27=24x+10
26x-24x=27+10
2x=37
x=37/2

6(x+1)-4(x-5)=3(x-7)-4(x-2)
6x+6-4x+20=3x-21-4x+8
2x+26=-x-13
3x=-26-13
3x=-39
x=-39/3
x=-13

5(3x+1)=7(x-2)-9(5-x)
15x+5=7x-14-45+9x
15x+5=16x-59
16x-15x=59+5
x=64

3(x+1)=4(x-6)+(x+7)
3x+3=4x-24+x+7
3x+3=5x-17
5x-3x=17+3
2x=20
x=20/2
x=10