Respuesta :

[tex]\begin{gathered} f(x)=\frac{2}{5}x-5 \\ \text{Now, f(x)=-9 in the above equation.} \\ -9=\frac{2}{5}x-5 \\ -9+5=\frac{2}{5}x \\ -4=\frac{2}{5}x \\ x=-10 \end{gathered}[/tex]