If said number is x, that means that twice (2 times) a number and 2x-7=13. Adding 7 to both sides, we get 2x=20 and by dividing both sides by 2 we get x=10. For 2, we see that the sum of a number and 6 is first priority, so we have (x+6)*7=-43. Dividing both sides by 7, we get x+6=-43/7. After that, we subtract both sides by 6 to get -43/7-6=x
List all the multiples of the numbers:
2: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100
5: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100
6: 6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72, 78, 84, 90, 96
9: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99
The least common multiple of 2, 5, 6, and 9 is 90.
