Question

quanto se deve subtrair de 3/4 para obter metade de 5/7?

Answer 1

$\frac{3}{4} -x= \frac{ \frac{5}{7} }{2} \\ \\ \frac{3}{4} -x=\frac{5}{7}. \frac{1}{2} \\ \\ \frac{3}{4} -x= \frac{5}{14} \\ \\ -x= \frac{5}{14} - \frac{3}{4} \\ \\ x= \frac{3}{4} - \frac{5}{14} \\ \\ x= \frac{3.7-5.2}{28} = \frac{21-10}{28} = \frac{11}{28}$

Answer 2

3/4 - x = 5/7/2
5/7 : 2
5/7 . 1/2=5/14
3/4 - x = 5/14
m.m.c(4,14) = 28
21 - 28 x = 10
---------------------------------- cortar o denominador devido a igualdade fica ;
               28

21 -28 x = 10
-28 x = 10 - 21 
-28 x = -11
x = -11/-28
x = 11/28