Question

Numa P.G de 4 termos o primeiro e -4 e a razao e -3.determine o ultimo.

Answer 1

$a_n=a_1\cdot q^{n-1}\\\\a_4=-4\cdot(-3)^{4-1}\\\\a_4=-4\cdot(-3)^3\\\\a_4=-4\cdot(-9)\\\\\boxed{a_4=36}$