[tex]\bf \stackrel{mixed}{3\frac{2}{7}}\implies \cfrac{3\cdot 7+2}{7}\implies \stackrel{improper}{\cfrac{23}{7}}~\hfill \stackrel{mixed}{4\frac{3}{7}}\implies \cfrac{4\cdot 7+3}{7}\implies \stackrel{improper}{\cfrac{31}{7}} \\\\\\ \stackrel{mixed}{5\frac{9}{14}}\implies \cfrac{5\cdot 14+9}{14}\implies \stackrel{improper}{\cfrac{79}{14}} \\\\[-0.35em] ~\dotfill[/tex]
[tex]\bf \left( \cfrac{23}{7}+\cfrac{31}{7} \right)-\cfrac{79}{14}\implies \left( \cfrac{23+31}{7} \right)-\cfrac{79}{14}\implies \cfrac{54}{7}-\cfrac{79}{14}\implies \stackrel{\textit{using an LCD of 14}}{\cfrac{(2)54-(1)79}{14}} \\\\\\ \cfrac{108-79}{14}\implies \cfrac{29}{14}\implies 2\frac{1}{14}[/tex]
