Bonjour, j’ai besoin d’aide pour ces 3 exercices merci à ceux qui m’aiderons

Réponse :

bjr

Explications étape par étape

ex 2

a)

3x - 5 = 3 +2x

3x-2x=3+5

x = 8

b)

2 - x = x +5

-x = x + 5 -2

-x = x +3

-3 = 2x

x = [tex]\frac{-3}{2}[/tex] = - 1,5

c)

6x + 7 = x -13

6x - x = -13-7

5x = -20

x = [tex]\frac{-20}{5}[/tex] = -4

d)

1+ x = -2x +4

x +2x = 4 - 1

3x = 3

[tex]\frac{3x}{3}[/tex]= [tex]\frac{3}{3}[/tex]

x = 1

ex 3

1. L'équation est : 3x - 4 = (x+3) ×( -2)

2.

3x - 4 = (x+3) ×( -2)

3x - 4 = (-2) × 3 + (-2) × x

3x - 4 = -2x -6

3x +2x = -6 + 4

5x = -2

[tex]\frac{5x}{5}[/tex] = [tex]\frac{-2}{5}[/tex]

x = -0,4

ex 4

a)

2(x+5) = 3(2x -2)

2×x + 2×5 = 3×2x + 3× (-2)

2x + 10 = 6x  - 6

10 +6 = 6x - 2x

16 = 4x

4x = 16

[tex]\frac{4x}{4}[/tex] = [tex]\frac{16}{4}[/tex]

x = 4

b)

2(x-2) - 4(1-x) = 4

2×x + 2 × (-2) - 4 × 1 -4 × (-x) = 4

2x - 4 -4 + 4x = 4

6x - 8 = 4

6x = 4 + 8

6x = 12

x = 2

c)

3(x-2) + 4 = 2 - x

3×x + 3 × (-2) +4 = 2 -x

3x -6 +4 = 2-x

3x-2 = 2-x

3x + x =  2+2

4x = 4

x = 1

d)

5(x + 1) = 3(3-x)

5×x + 5×1 = 3×3 + 3×(-x)

5x + 5 = 9 - 3x

5x + 3x = 9-5

8x = 4

x = 0,5

bonne continuation