aidez moi svp Résoudre dans R les équations suivangtes : a) 4x+7=31 b) 5x-8=3x+14 c)-2x+10=4x-13 d)7x-9=2(3x-1) e) x(x-1)+2x-2=(x-3)=-7x+17 f) (x-4)(x+1)-(x+7)(

Bonjour,

a) 4x+7=31

4x = 31 - 7

4x = 24

x = 24/4

x = 6

b) 5x-8=3x+14  

5x - 3x = 14 + 8

2x = 22

x = 22/2

x = 11

c)-2x+10=4x-13

- 2x - 4x = - 13 - 10

- 6x = - 23

x = 23/6

d)7x-9=2(3x-1)

7x - 9 = 6x - 2

7x - 6x = - 2 + 9

x = 7

e) x(x-1)+2x-2=(x-3)=-7x+17  --> Erreur d'énoncé

f) (x-4)(x+1)-(x+7)(x-3)=-7x+17

x² + x - 4x - 4 - (x² - 3x + 7x - 21) = - 7x + 17

x² + x - 4x - 4 - x² + 3x - 7x + 21 = - 7x + 17

x² - x² + x + 3x - 7x + 7x - 4x = 17 + 4 - 21

- x = 0

x = 0

g) 5x-7/9=2

45/9x - 7/9 = 18/9

45x - 7 = 18

45x = 18 + 7

45x = 25

x = 25/45

x = 5/9

h) x-3/4+2(x-4)/5-1/3=0

x - 3/4 + (2x - 8) / 5 - 1/3 = 0

60/60x - 45/60 + 24/60x - 96/60 - 20/60 = 0

60x - 45 + 24x - 96 - 20 = 0

60x + 24x = 45 + 96 + 20

84x = 161

x = 161/84

x = 23/12.

Réponse :

Bonjour

Explications étape par étape

Résoudre dans R les équations suivangtes :

a) 4x+7=31

4x = 31 - 7

x = 24/4

x = 6

b) 5x-8=3x+14

5x - 3x = 14 + 8

2x = 22

x = 22/2

x = 11

c)-2x+10=4x-13

4x + 2x = 10 + 13

6x = 23

x = 23/6

d)7x-9=2(3x-1)

7x - 9 = 6x - 2

7x - 6x = -2 + 9

x = 7

e) x(x-1)+2x-2=(x-3)=-7x+17 trop de égal ???

f) (x-4)(x+1)-(x+7)(x-3)=-7x+17

x^2 + x - 4x - 4 - (x^2 - 3x + 7x - 21) = -7x + 17

-3x - 4 - 4x + 21 = -7x + 17

7x - 3x = 17 - 17

4x = 0

x = 0

g) 5x-7/9=2

5x = 2 + 7/9

5x = 18/9 + 7/9

x = 25/9 / 5

x = 5/9

h) x-3/4+2(x-4)/5-1/3=0

(x - 3)/4 + 2(x - 4)/5 - 1/3 = 0

x/4 - 3/4 + 2x/5 - 8/5 - 1/3 = 0

5x/20 + 8x/20 = 32/20 + 15/20 + 1/3

13x/20 = 141/60 + 20/60

13x/20 = 161/20

x = 161/20 * 20/13

x = 161/13