Pouvez-vous m’aider s’il vous plaît j’ai des lacunes en maths

Réponse:

3°) 2x -5 +6x = 2 -6x +6x

2x +6x +6x -6x = 2 +5

2x +6x = 2+5. On supprime -6x et +6x , car ils sont deux nombres opposés.

8x = 7

8x/8 = 7/8

x = 7/8

4°) 8x -5 = 2

8x = 2+5

8x = 7

8x/8 = 7/8

x = 7/8

-(2x +3) -x+2 = 2-(x+7)

-2x -3 -x +2 = 2 -x -7

-2x -x +x = 2 -7 +3 -2

-2x = -7 +3

-2x = -4

-2x/-2 = -4/-2

x = 2

3(x-2) -4x = 2(x-5) +10

3x -6 -4x = 2x -10 +10

3x -4x -2x = -10 +10 +6

-x -2x = 6

-3x = 6

-3x/-3 = 6/-3

x = -2

5x -(4x-1) = 2 -6(2x -1/3) -3x

5x -4x +1 = 2 -12x +6/3 -3x

5x -4x +12x +3x = 2 +2 -1

x +15x = 4 -1

16x = 3

16x/16 = 3/16

x = 3/16

8/3x -3 = -(7+x)

8/3x -3 = -7 -x

8/3x +x = -7 +3

8/3x +3/3x = -4

11/3x = -4

11/3x × 3/11 = -4 × 3/11

x = -12/11

3/x -2 = 7

3/x = 7 +2

3/x = 9

x/3 = 1/9

x/3 × 3 = 1/9 × 3

x = 3/9

x = 1/3

x-4/3 = 7x-2/-2

-2(x-4) / -2×3 = 3(7x-2) / -2×3. simplifier l'équation en utilisant le produit en croix.

-2(x-4) = 3(7x-2). simplifier les deux membres de l'équation par -2×3.

-2x +8 = 21x -6

-2x -21x = -6-8

-23x = -14

-23x/-23 = -14/-23

x = 14/23

2(x -1/7) -5/7 = 7(x -2/21) -6x-2/3

2x -2/7 -5/7 = 7x -14/21 -6x-2/3

2x -7x = -2/3 -2/3 +2/7 +5/7

-5x = -4/3 +7/7

-5x = -4/3 +1

-5x = -4/3 +3/3

-5x = -1/3

-5x × 1/-5 = -1/3 × 1/-5

x = -1/15