Each number is decreasing by half.
There are infinitely many possible answers. One such is: Un = (-8n4 + 104n3 - 475n2 + 859n - 294)/6, for n = 1, 2, 3, ...
you add 10 to each number in the series of three. If you break the pattern into groups of three you will see 8-14-5 then 18-24-15 then 28-34. . . so 8+10=18+10=28, 14+10=24+10=34, 5+10=15+10=25, so continuing the pattern would be starting at 28: 28-34-25-38-44-35-48-54-45. . .
28 decreased by 25 percent = 21= 28 - (25% * 28)= 28 - (0.25 * 28)= 28 - 7= 21
25 x 28 = 700
t(n) = 3(n-1) + 1, for n = 1, 2, 3, etc
41/7 - 25/28 = 164/28 - 25/28 = 139/28 = 427/28
28/25 is in its simplest form.
28/25 = 28/25 you cant reduce that
There are many possibilities. One is: Un = (8n3 - 39n2 + 79n - 36)/6 for n = 1, 2, 3, ...
25
3 and 28 3 - 28 = -25 (or 28 - 3 = 25) 3 x 28 = 84