A base deve ser maior que 0 e diferente de 1, enão :

[tex]\displaystyle \sf \log_{\ (2x+8)} 0,02 \\\\ 2x+8 > 0 \\\\ 2x > - 8 \\\\ x > - 4 \\\\ \text{e a base diferente de 1} : \\\\ 2x+8 \neq 1 \\\\ 2x \neq 1-8 \\\\ 2x \neq -7 \\\\ x \neq \frac{-7}{2} \\\\ portanto : \\\\ \large\boxed{\sf \ x > -4 \ \ e \ \ x \neq \frac{-7}{2}\ }\checkmark[/tex]

letra b