gaokao 2015 Q12

gaokao · China · tianjin-science 5 marks Binomial Theorem (positive integer n) Find a Specific Coefficient in a Single Binomial Expansion

In the expansion of $\left(x - \frac{1}{4x}\right)^6$, the coefficient of $x^2$ is .

In the expansion of $\left(x - \frac{1}{4x}\right)^6$, the coefficient of $x^2$ is \underline{\hspace{2cm}}.