Question

CO 4 BAI NHE

THANKS

Answer 1

lam 2 bai thoi cung duoc nha 

Answer 2

Bài 6:

 \(\dfrac{11}{13}-\left(\dfrac{5}{42}-x\right)=-\left(\dfrac{15}{28}-\dfrac{11}{13}\right)\)

\(\Rightarrow\dfrac{11}{13}-\dfrac{5}{42}+x=-\dfrac{15}{28}+\dfrac{11}{13}\)

\(\Rightarrow x=-\dfrac{15}{28}+\dfrac{11}{13}-\dfrac{11}{13}+\dfrac{5}{42}=-\dfrac{5}{12}\)

Bài 2:

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

b) \(\Rightarrow x=\dfrac{3}{7}-\dfrac{1}{4}-\dfrac{3}{5}=-\dfrac{59}{140}\)

Answer 3

Bài 6:

\(\dfrac{11}{13}-\left(\dfrac{5}{42}-x\right)=-\left(\dfrac{15}{28}-\dfrac{11}{13}\right)\)

<=> \(\dfrac{11}{13}-\dfrac{5}{42}+x=-\dfrac{15}{28}+\dfrac{11}{13}\)

<=> \(x=-\dfrac{15}{28}+\dfrac{11}{13}-\dfrac{11}{13}-\dfrac{5}{42}\)

<=> \(x=-\dfrac{15}{28}-\dfrac{5}{42}\)

<=> \(x=\dfrac{-55}{84}\)

Bài 7:

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

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

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

<=> \(x=\dfrac{2}{5}\)

b. \(\dfrac{3}{7}-x=\dfrac{1}{4}-\left(-\dfrac{3}{5}\right)\)

<=> \(\dfrac{3}{7}-x=\dfrac{1}{4}+\dfrac{3}{5}\)

<=> \(-x=\dfrac{1}{4}+\dfrac{3}{5}-\dfrac{3}{7}\)

<=> \(-x=\dfrac{59}{140}\)

<=> \(x=\dfrac{-59}{140}\)

Answer 4

Bài 8:

a: Ta có: \(x+\dfrac{3}{10}=\dfrac{-2}{15}\)

\(\Leftrightarrow x=\dfrac{-2}{15}-\dfrac{3}{10}=\dfrac{-4}{30}-\dfrac{9}{30}=\dfrac{-13}{30}\)

b: Ta có: \(x+\dfrac{5}{6}=\dfrac{2}{5}-\left(-\dfrac{2}{3}\right)\)

\(\Leftrightarrow x+\dfrac{5}{6}=\dfrac{2}{3}+\dfrac{2}{5}=\dfrac{16}{15}\)

\(\Leftrightarrow x=\dfrac{16}{15}-\dfrac{5}{6}=\dfrac{96-75}{90}=\dfrac{7}{30}\)