How to use the binomial theorem to expand (2x+y)^4 ?

(2x+y)^4 = (2x)^4 + (4)(2x)^3(y) + (4 x3)/2! (2x)^2(y)^2 + (4 x 3 x 2)/3! (2x)(y)^3 + (4 x 3 x 2 x 1)/4! (2x)^0(y)^4

= 16x^4 + 32x^3y + 24 x^2y^2 + 8xy^3 + y^4

http://oi65.tinypic.com/eq4f2e.jpg

Expand (u+v)^4 by the binomial theorem and then replace u by 2x and v by y and simplify.