Using formal algebra, you could do something like this:
x = 1st integer
x+2 = 2nd
x+4 = 3rd
x+6 = 4th
Then write and solve the equation that says their sum is -124:
That equation is easily solved using basic algebra. Then use the solution to answer the question.
If formal algebra is not required, then there is a quick and easy path to the answer.
The average of the four even integers is -124/4 = -31. That means the four even integers are the two integers closest to, and on either side of, -31. Those four integers are -28, -30, -32, and -34.