Question

please help, step by step having difficulty here as well.

Find the term containing
x5 in the expansion of (x + 2y)^10

Answer 1

The term containing x^k in (x+z)^n is C(n,n-k)x^(n-k)z^k. So, we have

C(10,5)(x^5)(2y)^5 = 8064 x^5 y^5