Hệ phương trình đề \(\Leftrightarrow\)\(\left\{{}\begin{matrix}y=\frac{4}{3}x\\\frac{1}{2}\left(x^2-9\right)=\frac{1}{2}x\left(\frac{4}{3}x\right)+12\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}y=\frac{4}{3}x\\3x^2-3.9=4x^2+12.6\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}y=\frac{4}{3}x\\-99=x^2\left(KTM\right)\end{matrix}\right.\)
Vậy hpt vô nghiệm.