Question

Identify the third term in the expansion of (7x – 2y)^3

Answer 1

sub in a=7x, b=2y.

Answer 2

(a−b)^3=(a−b)(a−b)(a−b)
=(a−b)(a^2−2ba+b^3)
=(a^3−a^2b−2a^2b+2ab^2+ab^3−b^3)