Question

Bài 7 : 

a. x - 2/35 = -2/25 .                                          b.11/12 - ( x + 2/5 ) = 2/3 . 

                                               c. 2/5 + 1/4 . x = -3/10 . 

Answer 1

a. \(x-\dfrac{2}{35}=\dfrac{-2}{25}\)

<=> \(x=\dfrac{-2}{25}+\dfrac{2}{35}\)

<=> x = \(-\dfrac{4}{175}\)

b. \(\dfrac{11}{12}-\left(x+\dfrac{2}{5}\right)=\dfrac{2}{3}\)

<=> \(\dfrac{11}{12}-x-\dfrac{2}{5}=\dfrac{2}{3}\)

<=> \(-x=\dfrac{2}{3}-\dfrac{11}{12}+\dfrac{2}{5}\)

<=> \(-x=\dfrac{3}{20}\)

<=> \(x=\dfrac{-3}{20}\)

c. \(\dfrac{2}{5}+\dfrac{1}{4}x=\dfrac{-3}{10}\)

<=> \(\dfrac{1}{4}x=\dfrac{-3}{10}-\dfrac{2}{5}\)

<=> \(\dfrac{1}{4}x=\dfrac{-7}{10}\)

<=> \(x=\dfrac{-14}{5}\)

Answer 2

a) \(x-\dfrac{2}{35}=-\dfrac{2}{25}\)

\(\Rightarrow x=-\dfrac{2}{25}+\dfrac{2}{35}\)

\(\Rightarrow x=-\dfrac{4}{175}\)

b) \(\dfrac{11}{12}-\left(x+\dfrac{2}{5}\right)=\dfrac{2}{3}\)

\(\Rightarrow x+\dfrac{2}{5}=\dfrac{11}{12}-\dfrac{2}{3}\)

\(\Rightarrow x+\dfrac{2}{5}=\dfrac{1}{4}\)

\(\Rightarrow x=\dfrac{1}{4}-\dfrac{2}{5}\)

\(\Rightarrow x=-\dfrac{3}{20}\)

c) \(\dfrac{2}{5}+\dfrac{1}{4}x=-\dfrac{3}{10}\)

\(\Rightarrow\dfrac{1}{4}x=-\dfrac{3}{10}-\dfrac{2}{5}\)

\(\Rightarrow\dfrac{1}{4}x=-\dfrac{7}{10}\)

\(\Rightarrow x=-\dfrac{7}{10}:\dfrac{1}{4}\)

\(\Rightarrow x=-\dfrac{14}{5}\)