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    • Thread Starter

    Hi there i have just a couple of questions to ask on some Harder Binomial expansion stuff.

    1) How do you complete it with 2 brackets such as (5+2x)(3-2x)^5.

    2)How to find n and k given that (1+kx)^n = 1-4x+7x^2 +...

    Thanks. Clear explanations please, not just one liners that dont help at all!

    1) Expand each one individually first. In your example, you'll have (5+2x)(quintic polynomial in x), which you can then expand again.

    2) What should the coefficients of x and x^2 be in terms of k?

    One liners, but hopefully they help

    For the first one, do the expansion of the second bracket, then once you have the expansion, times the expansion by the first bracket.

    For the second one, sub in your numbers and constants into the binomial expansion equation. For example, the second term, you know kxn=-4x, so kn=-4. You will get simultaneous equations

    Hope that helps to get started
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Updated: April 13, 2011

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