1 and 3.
ANSWER: 9, 15, 21 are not prime numbers because these numbers have factors other than 1 and themselves. Therefore, 9, 15, 21 are composite numbersFactors of 9 other 1 and itself (9) : 3Factors of 15 other 1 and itself (15): 3, 5Factors of 21 other 1 and itself (21): 3, 7
The outlier in the set of numbers 9, 15, 15, 15, 16, 20, 21, 21, and 30 is 9 and 30. The number 9 is significantly lower than the rest of the values, while 30 is much higher, making both numbers stand out from the overall range of the dataset.
9, 15, 21
1, 3, 5, 7, 9, 15, 21, 35, 45, 63, 105, 315, -1, -3, -5, -7, -9, -15, -21, -35, -45, -63, -105, -315
Oh, dude, 9 and 21 both go into numbers that are multiples of both 9 and 21. So, like, they can go into numbers like 63, 126, 189, and so on. It's just basic math, nothing too mind-blowing.
12 numbers (including 21). The numbers are 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21.
The numbers that go into 45 are 1, 5, 9, 45
1 and 3 go into both.
9, 15, 21, 25, 27, 33
63 & 5 21 & 15 9 & 35
That's an infinite list. 9, 15, 21, 25, 27...
That's an infinite list, started by 9, 15 and 21.