Answer:
[3/4 + (-5/7)] = 1 /28
≅ 0.03571429
Step-by-step explanation:
[tex]\bf \cfrac{3}{4}+\left( -\cfrac{5}{7} \right)\implies \cfrac{3}{4}-\cfrac{5}{7}\implies \stackrel{\textit{our LCD will then be 28}}{\cfrac{(7)3~~-~~(4)5}{28}}\implies \cfrac{21-20}{28}\implies \cfrac{1}{28}[/tex]