Expand the following: (5x - 6y)^5

Answer 1

C(5,0)(5x)^5(6y)^0 - C(5,1)(5x)^4(6y)^1 + C(5,2)(5x)^3(6y)^2 - C(5,3)(5x)^2(6y)^3 + C(5,4)(5x)^1(6y)^4 - C(5,5)(5x)^0(6y)^5

where C(5,x) is number of combinations of 5 taken 2 at a time