Réponses

2012-09-16T12:05:06+02:00

4/(x+1) - 1/(x-1)= (3x-5)/(x²-1)

 4/(x+1) - 1/(x-1) - (3x-5)/(x²-1) = 0

 4(x-1)/(x+1)(x-1) - (x+1)/(x+1)(x-1) - (3x-5)/(x+1)(x-1) = 0

 [4(x-1) - (x+1) - (3x-5)]/(x+1)(x-1) = 0

 [4x-4 - x-1 - 3x+5]/(x+1)(x-1) = 0

 [3x-5 - 3x+5]/(x+1)(x-1) = 0

 [3x - 5 - 3x + 5]/(x+1)(x-1) = 0

 0 = 0

 

c'est démontré.

En espérant t'avoir aidé