Bonjour, pouvez vous m'aider à faire ces équations: [tex]5x + 11 = 9x -3\\12R - 6 = -2 + 5(8R + 2)\\6x^{2} + 9 = 3x (2x-5)[/tex]

5x + 11 = 9x - 3

5x - 9x = -3 - 11

-4x = - 14

x = 14/4 = 7/2 = 3,5

12R - 6 = -2 + 5(8R+2)

12R - 6 = -2 + 40R + 10              puisque k(a+b) = ka + kb (cours)

12R - 40R = -2 + 10 + 6

-28R = 14

R = -14/28 = -1/2

6x² + 9 = 3x (2x - 5)

6x² + 9 = 6x² - 15x

15x = -9

x = -9/15

Réponse :

Bonjour,

5x+11 = 9x-3

5x-9x+11-11 = 9x-9x-3-11

-4x = -14

x = -14/(-4)

x = 7/2

x = 3,5

12R-6 = -2+5*(8R+2)

12R-6+6 = -2+5*8R+5*2+6

12R = -2+40R+10+6

12R = 40R+14

12R-40R = 40R-40R+14

-28R = 14

R = 14/(-28)

R = -1/2

R = -0,5

6x²+9 = 3x*(2x-5)

6x²+9 = 3x*2x+3x*(-5)

6x²+9 = 6x²-15x

6x²-6x²+15x+9-9 = 6x²-6x²-15x+15x-9

15x = -9

x = -9/15

x = -3/5

x = -0,6