\(\bf \begin{cases}
y=-0.8x+12\impliedby &\textit{weekly demand}\\
y=0.03x^2-15x+18\impliedby &\textit{weekly supply}
\end{cases}
\\ \quad \\
\textit{when are they equal to each other?}\qquad y = y
\\ \quad \\
-0.8x+12=0.03x^2-15x+18\impliedby \textit{solve for "x"}\)
