Answer: 30
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Step-by-step explanation:
Method 1)
The short way to find this answer is to multiply the values together to get 6*15 = 90, then divide by the GCF 3 getting 90/3 = 30 as the LCM.
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Method 2)
The longer way is to list the prime factorizations of each value
6 = 2*3
15 = 3*5
The unique factors are: 2, 3, 5
The most that each unique factor happens is one time.
Those unique factors multiply out to 2*3*5 = 30
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Method 3)
Another way is to list out the multiples of 6 and 15
multiples of 6 = {6, 12, 18, 24, 30, 36, 42, 48, ...}
multiples of 15 = {15, 30, 45, 60, 75, 90, 105, ...}
We see that 30 is the smallest value in both sets, so 30 is the LCM.