Answer:
The equation a + d(n-1)
Explanation:
Where a is the first number in the sequence, d is the common difference and n is the position of a certain number in the series, e.g
1, 2, 3, 4, 5: a = 1, d = 1 (because 2-1=1, 3-2=1, 4-3=1, etc) and n = 1,2,3...
2, 4, 6, 8, 10: a = 2, d = 2 (because 4-2=2, 6-4=2, etc) and n = 1,2,3,4,5...
So for the second sequence, we could try to get the value of n in n = 6 as follows:
a + d(n-1) where a = 2, n = 6 and d = 2
Thus, 2 + 2(6-1) = 2 + 2(5) = 2 + 10 = 12
So the sixth number in the series would be 12