[tex]\\ \sf\longmapsto \dfrac{-3}{7}+\left(-\dfrac{3}{4}\right)[/tex]
[tex]\\ \sf\longmapsto \dfrac{-3}{7}-\dfrac{3}{4}[/tex]
[tex]\\ \sf\longmapsto \dfrac{-12-21}{28}[/tex]
[tex]\\ \sf\longmapsto \dfrac{-33}{28}[/tex]
