Resposta :
[tex]\Large\boxed{\begin{array}{l}\sf a_8=a_1\cdot q^7\\\sf a_8=(-5)\cdot 3^7\\\sf a_8=(-5)\cdot2187\\\sf a_8=-10935\end{array}}[/tex]
[tex]\Large\boxed{\begin{array}{l}\sf a_8=a_1\cdot q^7\\\sf a_8=(-5)\cdot 3^7\\\sf a_8=(-5)\cdot2187\\\sf a_8=-10935\end{array}}[/tex]