<gh_stars>1-10
\documentclass{article}

\usepackage{incgraph}
\usepackage{amsmath}
\usepackage{qtree}
\begin{document}

\begin{inctext}
\Tree
[.$=$
  [.$M_x$ ]
  [.$+$
    [.$M_x$ ]
    [.$C_1$ ]
  ]
]
\end{inctext}

\end{document}
