SOLUTION: The following question was answered by you, however, I am having a difficult time understanding the work that was provided. It was confusing - please try again. Write the follo

Algebra ->  Permutations -> SOLUTION: The following question was answered by you, however, I am having a difficult time understanding the work that was provided. It was confusing - please try again. Write the follo      Log On


   

Question 1177140: The following question was answered by you, however, I am having a difficult time understanding the work that was provided. It was confusing - please try again.
Write the following expression without using the factorial symbol...
nC3+nC2+nC1
Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.

nC3 = %28n%28n-1%29%2A%28n-2%29%29%2F%281%2A2%2A3%29

nC2 = %28n%2A%28n-1%29%29%2F2

nC1 = n

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These symbols  nCk  define the number of  COMBINATIONS  of  n  items taken  k  at a time.

On Combinations,  see introductory lessons
    - Introduction to Combinations
    - PROOF of the formula on the number of Combinations
    - Problems on Combinations
    - OVERVIEW of lessons on Permutations and Combinations
in this site.

Also,  you have this free of charge online textbook in ALGEBRA-II in this site
    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this online textbook under the topic  "Combinatorics: Combinations and permutations".


Save the link to this textbook together with its description

Free of charge online textbook in ALGEBRA-II
https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson

into your archive and use when it is needed.




Answer by greenestamps(13200) About Me  (Show Source):