Answer:
3
Explanation:
An arithmetic sequence is defined as a sequence of numbers such that the difference of terms is constant. This difference is known as the common difference, and with each term, the common difference continues to be added.
In this case, the common difference is -3, and your first term is 12. To continue the arithmetic sequence from 12, continue to add the common difference to your term.
12, 9, 6, 3, 0, -3, -6, -9, -12, -15...
For the sake of this problem, the fourth term in this sequence, as seen here, is 3.
However, if you want to solve a problem like this mathematically, use the arithmetic sequence formula: a_n = a_1 + common difference(n-1), where n represents the number term you're looking for. In this problem, the equation would look like:
a4 = 12 + -3(4-1) = 12 + -3(3) = 12-9 = 3