n, n + 2, n + 4 - three consecutive odd integers
the sum of the first and second is 31 less than 3 times the third:
n + (n + 2) = 3(n + 4) - 31 use distributive property
n + n + 2 = (3)(n) + (3)(4) - 31
2n + 2 = 3n + 12 - 31
2n + 3 = 3n - 19 subtract 2 from both sides
2n = 3n - 21 subtract 3n from both sides
-n = -21 change the signs
n = 21
n + 2 = 21 + 2 = 23
n + 4 = 21 + 4 = 25
Answer: 21, 23, 25