Verified answer

Are these two different sequences?

Well the first sequence would be an arithmetic sequence with a common difference of 10 and the first term being -1.

Plug said variables into the explicit term formula: tn= t1+d(n-1)

Therefore the formula for this sequence would be: tn=-1+10(n-1)

So when looking for the next three terms:

t5 = -1 +10(5-1) = 39

t6 = -1 +10(6-1) = 49

t7 = -1 +10(7-1) = 59

Since I can't figure out what the hell your second sequence is, I'll leave the geometric sequence formulas here.

An arithmetic sequence goes from one term to the next by always adding (or subtracting) the same value.

Formula for term value: tn= t1 + d(n-1)

Formula for summation/series : sn= (t1+tn)n / 2

A geometric sequence goes from one term to the next by always multiplying (or dividing) by the same value.

Formula for term value: tn= t1 * r^(n=1)

Formula for summation/series : sn= t1 (1 - r^n) / 1-r

If r < 1 and you're looking for the summation of all possible values before the sequence term equals 0, use sn= t1 / 1-r