Anonymous
Anonymous asked in Science & MathematicsMathematics · 1 decade ago

PreCalculus - Binomial Theorem: Find the coefficient of x^8 in the expansion (x^2+3)^7?

PreCalculus - Binomial Theorem (coefficient)

Formula: (n C n-j)*a^(n-j)*x^j

2 Answers

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  • 1 decade ago
    Best Answer

    Well in this case the formula would be

    (n C n-j)*a^(n-j)*(x^2)^j

    x^8 = (x^2)^4

    so j = 4

    n = 7

    n - j = 3

    a = 3

    So the term that contains x^8 is

    (7 C 3)*3^3*(x^2)^4

    = 35*27*x^8

    The coefficient of x^8 is 945.

  • marci
    Lv 4
    3 years ago

    The coefficient of x indoors the strengthen of (3x + 5)^5 (3x + 5)^5 = The coefficient of x = 5C4(3x)(5)^4 Coefficient of x = (5*4*3*2/4*3*2*a million)(3x)(625) Coefficient of x = 9375. ................ answer

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