Use the following formula:
[tex](a+b)^4=a^4+4a^3b+6a^2b^2+4ab^3+b^4[/tex]Let:
[tex]\begin{gathered} a=2x \\ b=y \end{gathered}[/tex]Therefore:
[tex]\begin{gathered} (2x+y)^4=(2x)^4+4(2x)^3y+6(2x)^2y^2+4(2x)y^3+y^4 \\ (2x+y)^4=16x^4+32x^3y+24x^2y^2+8xy^3+y^4 \end{gathered}[/tex]