Bonjour, Resoudre les equations suivantes : 12x * 4 = 20x + 28 (3x - 4)(2x + 5) = 0 2(3x - 4) - (2x + 5) = 0 (5x - 7)au carré = 0 x aucarré + 20x + 100 = 0 Merc

Réponse:

12x × 4 = 20x +28

48x = 20x +28

48x -20x = 28

28x = 28

28x/28 = 28/28

x = 1

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

3x-4 = 0

3x = 4

3x/3 = 4/3

x = 4/3

2x+5 = 0

2x = -5

2x/2 = -5/2

x = -5/2

L'équation a deux solutions : 4/3 ou -5/2.

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

6x -8 -2x -5 = 0

6x -2x = 8+5

4x = 13

4x/4 = 13/4

x = 13/4

(5x-7)² = 0

(5x-7)(5x-7) = 0

5x -7 = 0

5x = 7

5x/5 = 7/5

x = 7/5

5x -7 = 0

5x = 7

5x/5 = 7/5

x = 7/5

donc la solution de cette équation est : 7/5

x² +20x +100 = 0

x² +2×x×10 +10² = 0

(x+10)² = 0

(x+10)(x+10) = 0

x+10 = 0

x = -10