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Binomial theorum based Solved Anser Query.

  1. Aug 30, 2015 #1
    Dear Sir,

    Please help me to guide. The question is , Determine the seventh term, t[7], in the expansion of (2x - 3)[11].
    Ans is
    The seventh term is generated by substituting r = 6 into the general term formula.
    n = 11, a = 2x, b = -3, and r = 6,
    t[r+1] = [n]c[r]a[n-r]b[r]

    t[6+1] = [11]c[6]a[11-6]b[6]

    Please guide how [11]c[6] = 462

    t[7] = 462 (2x)[5]-3[6]

    With Regards
  2. jcsd
  3. Aug 31, 2015 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper

    The notation 11C6 means the number of groups of 6 items taken from a total of 11 items. It's called a combination and it is calculated using the formula:

    ## _nC_k=\frac{n!}{k!(n-k)!} ##

  4. Aug 31, 2015 #3
    Thank you for reply, sir.

    Could you please solve this using your formula step by step. Actually how to write the steps .

    With regards,

  5. Aug 31, 2015 #4
    Once again thank you sir, It is fully explain at wiki. and I Solved it.

    Thanks once's again.

    With Regards
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