What is the fourth term of the expansion of (1-2x)^n if the binomial coefficients are taken from the row of Pascal's triangle shown below?
1,6,15,20,15,6,1
"n" = [ the number of terms in a row - 1 ] ... So, we are expanding (1 - 2x)^6
The 4th term is given by C(6,3)*(-2x)^3 = 20 * (-8x^3) = -160x^3
