find coefficient of x^8 in expanding of (x-2)^11
the general term t(n+1) = C(11,n) x^(11-n) (-1)^n
so 11-n = 8
n = 3
so the 4th term is
C(11,3) x^8 (-1)^3
= -165x^8
or ..... start expanding using the elements of Pascals triangle
http://ptri1.tripod.com/
(x-2)^11
= 1x^11 (-1)^0 + 11x^10 (-1)^1 + 55x^9 (-1)^2 + 165x^8 (-1)^3 + ...
= x^11 - 11x^10 + 55x^9 - 165x^8 + 330x^7 - ...