Fungsi Invers

\begin{equation*}
\begin{split}
f(x) & = 2x - 6 \\\\
y & = 2x - 6 \\\\
-2x & = -y - 6 \quad {\color {blue} \text{bagi 2}} \\\\
x & = \tfrac 12 y + 3 \\\\
f^{-1} (x) & = \tfrac 12 x + 3
\end{split}
\end{equation*}