Let $a$ be a positive real number, $$\left(x + \frac{a - 7}{x}\right)^{13}$$ In the expansion of this expression, the coefficient of the $x^{11}$ term is $\frac{234}{a}$. Accordingly, what is $a$? A) 9 B) 12 C) 13 D) 15 E) 18
Let $a$ be a positive real number,
$$\left(x + \frac{a - 7}{x}\right)^{13}$$
In the expansion of this expression, the coefficient of the $x^{11}$ term is $\frac{234}{a}$.
Accordingly, what is $a$?
A) 9
B) 12
C) 13
D) 15
E) 18