Question

tìm x

a) \(\dfrac{3}{7}x-\dfrac{2}{3}x=\dfrac{10}{21}\)

b) \(\dfrac{7}{35}:\left(x-\dfrac{1}{3}\right)=-\dfrac{2}{25}\)

Answer 1

a) \(\dfrac{3}{7}x-\dfrac{2}{3}x=\dfrac{10}{21}\)

<=> \(x\left(\dfrac{3}{7}-\dfrac{2}{3}\right)=\dfrac{10}{21}\)

<=> \(x.\left(-\dfrac{5}{21}\right)=\dfrac{10}{21}\)

<=> \(x=-2\)

b) \(\dfrac{7}{35}:\left(x-\dfrac{1}{3}\right)=-\dfrac{2}{25}\)

<=> \(x-\dfrac{1}{3}=-\dfrac{5}{2}\)

<=> \(x=-\dfrac{13}{6}\)

Answer 2

a, \(\dfrac{3}{7}x-\dfrac{2}{3}x=\dfrac{10}{21}\)

\(\Leftrightarrow x\left(\dfrac{3}{7}-\dfrac{2}{3}\right)=\dfrac{10}{21}\)

\(\Leftrightarrow x.\dfrac{-5}{21}=\dfrac{10}{21}\)

\(\Leftrightarrow x=-2\)

Vậy ...

b, \(\dfrac{7}{35}:\left(x-\dfrac{1}{3}\right)=\dfrac{-2}{25}\)

\(\Leftrightarrow x-\dfrac{1}{3}=\dfrac{-5}{2}\)

\(\Leftrightarrow x=\dfrac{-13}{6}\)

Vậy ...

Answer 3

a)\(\dfrac{3}{7}x-\dfrac{2}{3}x=\dfrac{10}{21}\)

\(\left(\dfrac{3}{7}-\dfrac{2}{3}\right).x=\dfrac{10}{21}\)

\(-\dfrac{5}{21}\).x =\(\dfrac{10}{21}\)

x=\(\dfrac{10}{21}:-\dfrac{5}{21}\)

x = -2

b) \(\dfrac{7}{35}:\left(x-\dfrac{1}{3}\right)=-\dfrac{2}{25}\)

\(x-\dfrac{1}{3}\)= \(\dfrac{7}{35}:-\dfrac{2}{25}\)

\(x-\dfrac{1}{3}\) = \(-\dfrac{5}{2}\)

x = \(-\dfrac{5}{2}\) +\(\dfrac{1}{3}\)

x = \(-\dfrac{13}{6}\)