1) use binomial theorem, the first term must be to the 2, 2nd term to the 4th, to get those exponents, then you just do 6c4*(1/9)*16 which is 240/9 which is 80/3.

1) use binomial theorem, the first term must be to the 2, 2nd term to the 4th, to get those exponents, then you just do 6c4*(1/9)*16 which is 240/9 which is 80/3.