Question

[Ai Haibara]

Bài 1; Tính

a)\(\left(\dfrac{5}{18}-\dfrac{7}{24}+\dfrac{1}{9}\right):\dfrac{7}{18}\)

b)\(\left(\dfrac{7}{20}-\dfrac{5}{16}+\dfrac{3}{40}\right):\left(\dfrac{4}{15}-\dfrac{3}{10}+\dfrac{1}{12}\right)\)

Bài 2:Tìm x

a)\(\dfrac{3}{10}-x=\dfrac{5}{6}-\dfrac{2}{15}\)

b)\(\dfrac{-5}{8}+x=\dfrac{4}{9}-\dfrac{7}{1}\)

c)\(\dfrac{2}{x-3}=\dfrac{x-3}{18}\)

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Answer 1

[Công chúa cầu vồng]

a)\(\dfrac{3}{10}\)-x=\(\dfrac{25}{30}\)-\(\dfrac{4}{30}\)

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

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

x=\(\dfrac{-4}{10}\)

b)\(\dfrac{-5}{8}+x=\dfrac{4}{9}-\dfrac{63}{9}\)

\(\dfrac{-5}{9}+x=\dfrac{-59}{9}\)

\(x=\dfrac{-59}{9}-\dfrac{-5}{9}\)

\(x=\dfrac{-64}{9}\)

Answer 2

[Công chúa cầu vồng]

c)=>2.18=(x-3).(x-3)

=>36=(x-3)\(^2\)

=>6\(^2\)=(x-3)\(^2\)

6= x-3

x=6+3=9