Answer:
72, 504, 172
Explanation:
Let the unknown number be denoted as "x"
The second number = 7x
And the third number = 100 + x
(x) + (7x) + (100 + x) = 748
x + 7x + x + 100 = 748
9x + 100 = 748
9x = 748- 100
9x = 648
x = 648/9
x = 72
The first number = 72
The second number = 7x = 7 × 72 = 504
The third number = 100 + x = 100 + 72 = 172