>>838
(1)
C(5,2) ((3a)^3)((4b)^2) = 10*(3^3)*(4^2) (a^3)(b^2) = 4320 (a^3)(b^2)
4320

(2)
C(6,2) (a^2) ((-2b)^4) = 15*(2^4) (a^2) (b^4) = 240 (a^2) (b^4)
240