Respuesta :

Cathenna

Answer:

[tex] \boxed{f = -6} [/tex]

Step-by-step explanation:

[tex] = > - 7f - 9 = 9 - 4f \\ \\ = > - 7f + 4f - 9 = 9 \\ \\ = > - 3f = 9 + 9 \\ \\ = > - 3f = 18 \\ \\ = > 3f = - 18 \\ \\ = > f = - \frac{18}{3} \\ \\ = > f = - 6[/tex]