Let $a_1, a_2$ be first two terms and $a_3, a_5$ be third and fifth terms respectively. according to question $a_1 + a_2$ = – 4 ⇒ a + ar = – 4 ⇒ a(1 + r) = – 4 ....(i) and $a_5$ = $4a_3$ ⇒ $ar^4$ = $4ar^2$ ⇒ $r^2$ = 4 ⇒ r = ± 2 If r = 2, then (i) becomes a(1 + 2) = – 4 ⇒a = If r = – 2, then (i) becomes a (1 – 2) = – 4 ⇒ a = 4 When a = $\frac{-4}{3}$ and r = 2, then G.P. is $\frac{-4}{3},\frac{-8}{3},\frac{-16}{3}$ , ... When a = 4 and r = – 2, then G.P. is 4, – 8, 16, – 32, ........ .