bonjour, pouvez vous m'aider svp : 7+a=17+3a / 2(b+4)=-2 / 2(4x-5)=7x-5 merci​

Réponse:

7 +a = 17 +3a

a -3a = 17 -7

-2a = 10

-2a/-2 = 10/-2

a = -5

2(b +4) = -2

2×b + 2×4 = -2

2b +8 = -2

2b = -2 -8

2b = -10

2b/2 = -10/2

b = -5

2(4x -5) = 7x -5

2×4x - 2×5 = 7x -5

8x -10 = 7x -5

8x -7x = -5 +10

x = 5