CONTROLE DE MATHEMATIQUES N°3 3° Mercredi 1

CONTROLE DE MATHEMATIQUES N°3 3°

Mercredi 1^er décembre 2021

Exercice n°1

Résoudre les équations suivantes 4x – 1 = 6x + 7

4x – 6x = 7 +1 -2x = 8 x = 8

-2 x = -4

3(2x – 5) = 8 – (-6x + 5) 6x – 15 = 8 + 6x – 5 6x – 15 = 6x + 3 6x – 6x = 15 + 3 0x = 18

Aucune solution (x + 8)(2x – 5) = 0 x + 8 =0 ou 2x – 5 =0

x = -8 2x = 5 x = 5/2 S = {-8 ; 5

2 } 9x² - 16 = 0 (3x)² - 4² = 0 (3x – 4) (3x + 4) = 0 3x – 4 = 0 ou 3x + 4 =0 3x = 4 3x = -4 x = 4

3 x = - 4 3 S = {- 4

3 ; 4 3 } 30x² = 20x

30x² - 20x = 0 10x(3x -2) = 0 10x = 0 ou 3x – 2 =0 x = 0 3x =2 x = 2/3 S ={0 ; 2

3 } x² = 121

x = 11 ou x = -11 S ={-11 ; 11}

3x² + 10 = 2 3x² = 2 – 10 3x² = -8 Aucune solution