Question

1.\(\dfrac{5}{7}+\dfrac{2}{3}\cdot x=\dfrac{3}{10}\)

2.\(\left(x-\dfrac{1}{2}\right):\dfrac{1}{3}+\dfrac{5}{7}=9\dfrac{5}{7}\)

Answer 1

Câu 1 :

\(\dfrac{5}{7}\)+ \(\dfrac{2}{3}\). x =\(\dfrac{3}{10}\)

=> \(\dfrac{2}{3}\).x = \(\dfrac{3}{10}\) - \(\dfrac{5}{7}\)

=> \(\dfrac{2}{3}\). x = \(\dfrac{-29}{70}\)

=> x = \(\dfrac{-29}{70}\): \(\dfrac{2}{3}\)

=> x = \(\dfrac{-87}{140}\)

Answer 2

1. \(\dfrac{5}{7}+\dfrac{2}{3}.x=\dfrac{3}{10}\)

<=>\(\dfrac{2}{3}.x=\dfrac{3}{10}-\dfrac{5}{7}=-\dfrac{29}{70}\)

<=>\(x=-\dfrac{29}{70}:\dfrac{2}{3}=-\dfrac{87}{140}\)

Vậy x=\(-\dfrac{87}{140}\)

2.

Answer 3

Câu 2 : ( x - \(\dfrac{1}{2}\)) : \(\dfrac{1}{3}\)+ \(\dfrac{5}{7}\) = 9\(\dfrac{5}{7}\)

=> ( x - \(\dfrac{1}{2}\)) : \(\dfrac{1}{3}\)= 9

=> x - \(\dfrac{1}{2}\)= 9 . \(\dfrac{1}{3}\)

=> x - \(\dfrac{1}{2}\)= 3

=> x = 3 + \(\dfrac{1}{2}\)

=> x = \(\dfrac{7}{2}\)

Chúc bạn học tốt !

Answer 4

1)

\(\dfrac{5}{7}+\dfrac{2}{3}.x=\dfrac{3}{10}\\ \dfrac{2}{3}.x=\dfrac{3}{10}-\dfrac{5}{7}\\ \dfrac{2}{3}.x=\dfrac{21-50}{70}\\ =\dfrac{2}{3}.x=-\dfrac{29}{70}\\ x=-\dfrac{29}{70}.\dfrac{3}{2}\\ x=-\dfrac{87}{140}\)

2)

\(\left(x-\dfrac{1}{2}\right):\dfrac{1}{3}+\dfrac{5}{7}=9\dfrac{5}{7}\\ \left(x-\dfrac{1}{2}\right):\dfrac{1}{3}=\dfrac{68}{7}-\dfrac{5}{7}\\ \left(x-\dfrac{1}{2}\right):\dfrac{1}{3}=9\\ x-\dfrac{1}{2}=9.\dfrac{1}{3}\\ x-\dfrac{1}{2}=3\\ x=3+\dfrac{1}{2}\\ x=\dfrac{18+3}{6}\\ x=\dfrac{21}{6}\\ x=\dfrac{7}{2}\)