Answer: 220
Step-by-step explanation:
When we wanto to create a group of K elements for a set of N elements (where the order of the K elements does not matter, so we do not considerate the permutations of the K elements), the number of possible combinations is:

Here N = 12 and K = 3

So there are 220 possible combinations
Answer:

Step-by-step explanation:
The recursive rule tells you the initial term of the sequence is a1 = -3, and the common difference is d=7. (7 is the value added to one term to get the next term.)
Putting these values into the formula for the explicit rule gives ...
an = a1 +d(n -1)
an = -3 + 7(n -1)
The first multiple of 6 is 1 and 6, so 1+6=7