\[30n - 4(n + 2)^{2} =\]
\[= 30n - 4\left( n^{2} + 4n + 4 \right) =\]
\[= 30n - 4n^{2} - 16n - 16 =\]
\[= - 4n^{2} + 14n - 16.\]