Respuesta :
first off you'd want to change the mixed fraction to "improper", and then proceed, let's do so,
[tex]\bf \stackrel{mixed}{7\frac{3}{4}}\implies \cfrac{7\cdot 4+3}{4}\implies \stackrel{improper}{\cfrac{31}{4}} \\\\\\ \cfrac{31}{4}~-~3\implies \cfrac{31}{4}~-~\cfrac{3}{1}\impliedby \textit{our LCD is 4}\implies \cfrac{31-12}{4} \\\\\\ \cfrac{19}{4}\implies 4\frac{3}{4}[/tex]
[tex]\bf \stackrel{mixed}{7\frac{3}{4}}\implies \cfrac{7\cdot 4+3}{4}\implies \stackrel{improper}{\cfrac{31}{4}} \\\\\\ \cfrac{31}{4}~-~3\implies \cfrac{31}{4}~-~\cfrac{3}{1}\impliedby \textit{our LCD is 4}\implies \cfrac{31-12}{4} \\\\\\ \cfrac{19}{4}\implies 4\frac{3}{4}[/tex]