Question

Given the geometric series 256+p+64-32+
Determine the value of p

Answer 1

128

Obviously the common ratio

r = 1 / 2 = 0.5


256 ∙ 0.5 = 128

128 ∙ 0.5 = 64

64∙ 0.5 = 32

Answer 2

Actually the -32 tells us p = -128 with a common ratio of -1/2

64/p = -32/64
-32p = 4096
p = -128

Answer 3

T2/T1 = T3/T2
P/256 = 64/P
Then you cross multiply
P squared = 16 384
Put square root on both sides
P = -128
Note that the answer of the square root has +/-