4 .subtract the H. C. F of 8, 12 and
16 From the H. C. F OF 14 and 28.

HCF 8, 12, 16 = 4

HCF 14, 28 = 14

14 - 4 = 10

answer:

at time x=0 we have 1000, at time x=1 we have 2000, at time x=2 we have 4000.  

so that's an initial value of 1000 and a ratio of 2,

y = 1000 (2^x)

hope this !

first, let's see what the pattern is.

58 - x = 47

46 - x = 36

x = 9

so this means that the term after 25 is 25 - 9:

the next term in the sequence is 16.