Résous les équations suivantes : exercice 11 pages 100

4(x + 5) = 10x + 3
4x + 20 = 10x + 3
20 - 3 = 10x - 4x
17 = 6x
17/6 = x

3(x - 2) = 6(x + 4)
3x - 6 = 6x - 24
- 6 + 24 = 6x - 3x
18 = 3x
18/3 = x
6 = x

7x - (5x + 3) = 5(x - 3) + 2
7x - 5x - 3 = 5x - 15 + 2
- 3 + 15 - 2 = 5x - 7x + 5x
10 = 3x
10/3 = x

7(n + 2) - 3 = 25 - (3n + 4)
7n - 14 - 3 = 25 - 3n - 4
7n + 3n = 25 - 4 + 3 + 14
10n = 38
n = 38/10
n = 19/5

4y + 3(4y - 2) = 3(y + 1)
4y + 12y - 6 = 3y + 3
4y + 12y - 3y = 3 + 6
13y = 9
y = 9/13