The instructions revolve around the second number

so this must be x

the first number is 7 less than the second, so

x - 7

the third number is 3 times the second, so

3x

putting these puzzle pieces together, we get

(x - 7) + x + 3x = 98

now we solve for x

(x - 7) + x + 3x = 98

5x = 105

x = 21

The numbers in question are

21 - 7 = 14
21
21(3) = 63

Answer: 14, 21, 63