Réponse:
1 ) 3x+2= 0 , x= -2/3
2)
[tex] \frac{2x + 1}{x + 5} = 4 \\ 2x + 1 = 4(x + 5) \\ 2x + 1 = 4x + 20 \\ - 19 = 2x \\ x = - \frac{19}{2} [/tex]
3)
[tex] \frac{2}{x + 1} = \frac{3}{x - 1} \\ 2(x - 1) = 3(x + 1) \\ 2x - 2 = 3x + 3 \\ x = - 5[/tex]
4)
[tex] \frac{2x - 3}{x + 7} - \frac{2x + 1}{x - 4} = 0 \\ \frac{(2x - 3)(x - 4) - (x + 7)(2x +1 ) }{(x + 7)(x - 4)} = 0 \\ \frac{ {2x}^{2} - 3x - 8x + 12x - {2x}^{2} - 15x-7 }{(x + 7)(x - 4)} = 0 \\ \frac{ - 26x + 5}{(x - 4)(x + 7)} = 0 \\ on \: a \: donc \: - 26x + 5 = 0 \\ x = \frac{5}{26} [/tex]
