9514 1404 393
Answer:
-11/28, -5/14, -9/28
Explanation:
If we express these fractions using a denominator of 28, then we are looking for three numbers between -12/28 and -8/28. We can use numerators of -11, -10, and -9 to give 3 evenly-spaced numbers in the desired interval.
One set of possibilities is ...
-11/28
-10/28 = -5/14
-9/28
_____
Additional comment
There are an infinite number of rational numbers between any pair of numbers. One way to look at this problem is using decimal equivalents.
-3/7 ≈ -0.42857
-2/7 ≈ -0.28571
So, we could use, for example, -0.2858, -0.2859, -0.286, -0.2861.