5, 2, -1, -4,a. subtract 3; -7, -10, -13 b. add 3; -7, -10, -13 c. subtract -3; 7, 10, 13 d. add 3; 1, 4, 7

5 --> 2 is subtract 3
2 --> -1 is subtract 3
-1 --> -4 is subtract 3
Let's apply this rule until all blanks are filled.

5, 2, -1, -4, ___, ___, ___,...
We have three blanks, so let's continue from -4 three times.
-4 -(3) = -7

5, 2, -1, -4, -7, ___, ___,...
We have one blank filled.

-7 -(3) = -10

5, 2, -1, -4, -7, -10, ___,...
We have two blanks filled.

-10 -(3) = -13

5, 2, -1, -4, -7, -10, -13,...
We have all three blanks filled- let's see our answers.

We have:
-7
-10
-13

These are your three answers.

I hope this helps!