Question

Find the next two terms of the following geometric sequence.
5, – 20, 80,...

Answer 1

Heya!!

a= 5
a2= -20
a3= 80
$common \: difference \: = \frac{a2}{a1} = \frac{a3}{a2}$

Common ratio= -4

a4 = ar³= 5× (-4)³ = 5×(-64) = -512
a5=a ${r}^{4}$ = 5× ${(-4)}^{4}$ = 5× 256 = 1280

So next term of this GP are:

-512 and 1280