Finding consecutive even integers that add up to a certain number is similar to the process for finding consecutive integers that to a certain number, except that the integers are two apart from each other instead of one.

If you are trying to find n consecutive even integers whose sum is x, and n is an odd number, then the middle number is x/n, and the other numbers go up and down by two each.

Specifically in this case, n is 3 and x is -30. Divide -30/3 and you get -10. So the three numbers are -12, -10, and -8. Add them up and you get -30.