Answer:
For 1, you'd have 14, 7, 0, -7
Explanation:
Remember arithmetic sequences are adding the same thing (the difference) over and over and over. So in this case, you have the following:
1st blank: 14 + d
2nd blank: 1st blank + d OR (14 + d) + d = 14 + 2d
the -7 then is the 2nd blank + x OR [(14 + d) + d] + d
So you are adding 3d to the 14 to get to the -7. Set that up as the equation:
14 + 3d = -7.
When you solve for d, you get -7. That's what you'll add to 14 to get the first number, then add it again to get the second, etc.
The coefficient in front of d will always be one more than the number of spaces since you are adding the difference to find each blank IN ADDITION TO the last number in the sequence. So #4 would be setup like this:
2 + 5d = 57
Good luck!