If x is the smallest integer, x+4 is the largest. The given relationship can then be written as
(x+4) + 2x = 25 . . . . the equation used to solve the problem
3x = 21 . . . . . . . . simplify, subtract 4
x = 7 . . . . . . . . . . divide by 3
The integers are 7, 9, 11.