Replace x with the possible answers and solve to see which ones make the equation true:
5(3) = 15 + 4 = 19. 19 is < 29 so 3 works.
5(4) = 20 + 4 = 24. 24 is < 29, so 4 also works.
5(5) = 25 + 4 = 29. 29 is not less than 29 so doesn't work.
Only 3 and 4 will work.
The answer would be {3,4}
