Answer:
125, 100
Explanation:
Perhaps the terms of your series are supposed to be ...
__, __, 80, 64, 51.2, 40.96, ...
The common ratio is 64/80 = 0.8, so the recursive relation is ...
t[n] = 0.8×t[n-1]
__
Solving for the previous term, we find ...
t[n]/0.8 = t[n-1] . . . . . . divide by 0.8
or ...
t[n-1] = 1.25×t[n] . . . . . rearrange
Then the term previous to 80 is 1.25×80 = 100.
And the term previous to 100 is 1.25×100 = 125.
The first two terms of the geometric sequence are 125 and 100.