TeX source:

\begin{aligned} &\left\{\begin{array}{l} \text { area bounded by the graphs } \\ \text { of } \mathrm{f} \text { and } \mathrm{g} \text { and vertical } \\ \text { lines at } x=\mathrm{a} \text { and } x=\mathrm{b} \end{array}\right\}=\int_{\mathrm{a}}^{\mathrm{b}}\{\mathrm{f}(x)-\mathrm{g}(x)\} \mathrm{dx} . \end{aligned}