Determine the coefficeint of expansions.

1. Determine the coefficeint of x^9 y^3 in the expansion of

a) (x+y)^12

b) (x+2y)^12

c)(2x-3y)^12

2. Determine the coefficeint of

a) xyz^2 in (x+y+z)^4

b) xyz^2 in (w+x+y+z)^4

c) xyz^2 in (2x-y-z)^4

d) xyz^(-2) in (x-2y+3z^(-1))^4

e) w^3x^2yz^2 in (2w-x+3y-2z)^8