Answer:
18 and 3
Explanation:
If the lowest common multiple is 18, that means both numbers must be factors of 18, so each number could be 1,2,3,3,6,9 or 18.
If the greatest common factor is 6, that means both numbers must be divisible by 6, so each number could be 6,12,18,24,30 etc.
The only numbers found in both of these sets are 6 and 18, so there is your answer.
Hope this helps.