Question 631115
Use the Binomial Theorem to find the coeficient of 1/x in the expansion of (2x + 1/x)^3
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{{{(a+b)^3 = a^3 + 3a^2b + 3ab^2 + b^3}}}
{{{(2x + 1/x)^3 = 8x^3 + 3*4x^2*(1/x) + 3*2x*(1/x^2) + 1/x^3}}}
= {{{8x^3 + 12x + 6*(1/x) + 1/x^3}}}
= 6