Operasi Fungsi 1

\begin{equation*}
\begin{split}
f(x) & = x^2 - 4 \\\\
f(2x + 1) & = (2x + 1)^2 - 4 \\\\
f(2x + 1) & = 4x^2 + 4x + 1 - 4 \\\\
f(2x + 1) & = 4x^2 + 4x - 3
\end{split}
\end{equation*}