Even integer can be represented by 2n. 3 consecutive integers are 2n, 2n+2 and 2n+4 whose sum must be even. But 87 is an odd number! So the question is wrongly presented. 3 consecutive odd integers are 2n+1, 2n+3, 2n+5 and their sum is 6n+9=87; 6n=78 so n=13 and the integers are 27, 29 and 31.
If the first integer is even and the other two are consecutive: the sum of 2n, 2n+1, 2n+2=6n+3=87; 6n=84, n=14 and the integers are 28, 29, 30.