maths
posted by Shane on .
In the expansion of (12x)^11 the coefficient of x^3 is k times the coefficient of x^2. Evaluate k.

(12x)^11
= 1 + 11(2x) + 55(2x)^2 + 165(2x)^3 + ...
= 1  22x + 220x^2  1320x^3 + ...
so (220)k = 1320
k = 6