Find a Specific Coefficient in a Single Binomial Expansion
The question asks to find the coefficient of a specified power of x (or a constant term) in the expansion of a single binomial expression like (ax^m + bx^k)^n.
Where $m$ and $n$ are integers, $$\left(x^2 + 2y\right)^7$$ In the expansion of this expression, if one of the terms is $mx^ny^2$, what is the sum $m + n$? A) 56 B) 64 C) 72 D) 86 E) 94