(Math Quiz 10 – CT) In the expansion ({left( {2x – 5y} right)^8}), the coefficient of the containing term ({x^5}. {y^3}) is:


  • Question:

    In the expansion \({\left( {2x – 5y} \right)^8}\), the coefficient of the term containing \({x^5}.{y^3}\) is:

    Reference explanation:

    Correct answer: A

    The general term in the above expansion is

    \(\begin{array}{l}
    {T_{k + 1}} = {\left( { – 1} \right)^k}C_8^k. {\left( {2x} \right)^{8 – k}}{\left( {5y} \right)^k}\\
    = {\left( { – 1} \right)^k}C_8^k{.2^{8 – k}}{5^k}. {x^{8 – k}}. {y^k}
    \end{array}\)

    Requires the problem to occur when. Then the coefficient of the term containing \({x^5}.{y^3}\) is:−22400

    ADSENSE

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