hi, i need some help with the following questions! I would greatly appreciate it and the sooner the better! I really don't know how to do these, i'm basically stuck on them.. I have tried to solve them but I don't get the correct answer. Thank you so much!!(adsbygoogle = window.adsbygoogle || []).push({});

1) a universal set of length 'n' contains the letter 'A'. Prove that the fraction of the subsets of size 'r' that include the letter 'A' is (r/n).

2)in the expansion of (2x+1/x), find the term that does not include x.

3) Find the coefficient of x^12 in (1/x- 3x^2)^24

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# Homework Help: Math help!

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