Find the term indicated in the expansion. (x - 3y) 11; 8th term

The term in the expansion:

T (k+1) = n C k * A^ (n-k) * B^k.

In this case: n = 11, k + 1 = 8, so k = 7.

A = x, B = - 3 y

T 8 = 11 C 7 * x^ (11-7) * ( - 3 y) ^7 =

= (11 * 10 * 9 * 8 * 7 * 6 * 5) / (7 * 6 * 5 * 4 * 3 * 2 * 1) * x^4 * ( - 2,187 y^7) =

= 330 * ( - 2,187) x^4 y^7 = - 721,710 x^4 y^7

Answer: The 8th term in expansion is