Bonjour pouvez vous m'aider ce son des maths : Résoudre les équations suivantes en détaillant : a ) 5x=3 b ) 5+x=3 c ) 7x-4=5x+10 d ) 10+2x=0 e ) (10+2x)+(8-x)=

Hello,

5x = 3

x = 3/5

5 + x = 3

x = 3 - 5

x = -2

7x - 4 = 5x + 10

7x - 5x = 10 + 4

2x = 14

x = 14/2 = 7

10 + 2x = 0

2x = 0 - 10

2x = -10

x = -10/2 = -5

(10 + 2x) + (8 - x) = 0

10 + 2x + 8 - x = 0

x + 18 = 0

x = 0 - 18 = -18

-3x = 9

x = -9/3 = -3

Réponse :

a) 5x = 3

   5x/5 = 3/5

   x = 3/5

b) 5 + x = 3

   5 + x - 5 = 3 - 5

   x = -2

c) 7x - 4 = 5x + 10

  7x - 4 + 4 = 5x + 10 + 4

  7x - 5x = 5x + 14 - 5x

  2x = 14

  2x / 2 = 14 / 2

  x = 7

d) 10 + 2x = 0

   10 + 2x - 10 = 0 - 10

   2x / 2 = -10 / 2

   x = -5

e) (10+2x) + (8-x) = 0

  10 + 2x + 8 - x = 0

10 + 2x + 8 - x - 10 - 8 = -10 - 8

x = -18

f) -3x = 9

  -3x / -3 = 9/-3

  x = -3