cc ses pour savoir si vous pouvez m'aider

Bonsoir,

a.
5/3 x=4
x=4/(5/3)
x=12/5
S={12/5}

b.
6x-7=8
6x=15
x=15/6
S={15/6}

c.
8-7x=57
-7x=49
x=-7
S={-7}

d.
2x-11=7x+4
-5x=15
x=-3
S={-3}

e.
6-3x=15+4x
-7x=9
x=-9/7
S={-9/7}

Bonsoir,

5/3 x = 4
x = 4 * 3/5
x = 12/5

6x - 7 = 8
6x = 8 + 7
x = 15/6
x = 5/2

8 - 7x = 57
7x = 8 - 57
x = (-49)/7
x = -7

2x - 11 = 7x + 4
7x - 2x = - 11 - 4
5x = -15
x = -15/5
x = -3

6 - 3x = 15 + 4x

Tu fais la dernière ? On trouve x = -9/7