Question

Which expression represents the fourth term in the binomial expansion of (e+2f)10

Answer 1

Answer: it's A on edge

Answer 2

a = e; b = 2 f; n = 10.
The fourth term is:
T 4 = T (3+1) = ( 10 * 9 * 8 ) / ( 3 * 2 * 1 ) * e^7 * ( 2 f ) ^3 =
= 120 * e^7 * 2^3 * b^3 =
= 120 * 8 * e^7 * b^3 =
= 960 * e^7 * b^3