A= 3/x+2=4/7 B= x-1/x+3=4/5 aidez moi et Merci d'avance

     A= 3/x+2=4/74(x+2)=3x7
4x+8=21
4x=21-8
4x=13
x=13/4

B= x-1/x+3=4/5
5(x-1)=4(x+3)
5x-5=4x+12
5x-4x=12+5
x=17

Et Voila =D

Salut,

[tex] \frac{3}{x+2} = \frac{4}{7} \\ \frac{3}{x+2} - \frac{4}{7} = 0\\ \frac{3*7-4(x+2)}{7(x+2)} = 0\\ \frac{21 - 4x - 8 }{7(x+2)} = 0 \\ 13- 4x = 0\\ -4x = -13\\ 4x = 13\\ x = \frac{13}{4} [/tex]

S = {13/4}

[tex] \frac{x-1}{x+3} = \frac{4}{5}\\ \frac{x-1}{x+3} - \frac{4}{5} = 0\\ \frac{5(x-1) - 4(x+3)}{5(x+3)} = 0\\ \frac{5x - 5 - 4x - 12}{5(x+3)} = 0 \\ x - 17 = 0\\ x = 17[/tex]

S = {17}

Bonne soirée !