Số đối của \(\dfrac{7}{13}\) là \(\dfrac{-7}{13}\)

Bài 1:

a) \(\dfrac{5}{7}+\left(\dfrac{3}{5}+\dfrac{-5}{7}\right)\)\(=\left(\dfrac{5}{7}+\dfrac{-5}{7}\right)+\dfrac{3}{5}\)\(=0+\dfrac{3}{5}=\dfrac{3}{5}\)

b) \(\dfrac{-3}{4}-\dfrac{15}{14}:\dfrac{-5}{7}+\left(-1\right)^2\)\(=\dfrac{-3}{4}-\dfrac{15}{14}:\dfrac{-5}{7}+1\)\(=\dfrac{-3}{4}-\dfrac{-3}{2}+1\)

                                            \(=\dfrac{3}{4}+1\)\(=\dfrac{7}{4}\)

Giải:

\(243:3^4\)\(=243:81=3\)

\(10^9:10000=1000000000:10000=100000\)

Cái cây ko phải từ láy

Động từ đang

Bài 2:

a)\(1\dfrac{2}{3}x=\dfrac{-5}{6}\)

    \(\dfrac{5}{3}x=\dfrac{-5}{6}\)

       \(x\)\(=\dfrac{-5}{6}:\dfrac{5}{3}\)

      \(x=\dfrac{-1}{2}\)

c) \(\dfrac{-4}{5}:x+\dfrac{1}{2}=\dfrac{7}{10}\)

    \(\dfrac{-4}{5}:x\)        \(=\dfrac{7}{10}-\dfrac{1}{2}\)

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

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

             \(x\)         \(=-4\)

Bài 1:

a) \(\dfrac{1}{10}-\dfrac{1}{2}+\dfrac{7}{5}\)

\(=\dfrac{-2}{5}+\dfrac{7}{5}\)

\(=1\)

b) \(7\dfrac{5}{9}-\left(2\dfrac{5}{9}-1\dfrac{4}{7}\right)\)

\(=\)\(\left(7-2-1\right)+\left(\dfrac{5}{9}-\dfrac{5}{9}\right)+\dfrac{4}{7}\)

\(=4+0+\dfrac{4}{7}\)

\(=4\dfrac{4}{7}\)

\(=\dfrac{32}{7}\)

c) \(\dfrac{-6}{11}.\dfrac{8}{17}+\dfrac{-6}{11}.\dfrac{9}{17}+\dfrac{-5}{11}\)

\(=\dfrac{-48}{187}+\dfrac{-54}{187}+\dfrac{-5}{11}\)

\(=\dfrac{-6}{11}+\dfrac{-5}{11}\)

\(=-1\)

d) \(\dfrac{2}{3}.\dfrac{2}{5}+25\%-0,7:\dfrac{6}{5}\)

\(=\dfrac{2}{3}.\dfrac{2}{5}+\dfrac{1}{4}-\dfrac{7}{10}:\dfrac{6}{5}\)

\(=\dfrac{4}{15}+\dfrac{1}{4}-\dfrac{7}{12}\)

\(=\dfrac{-1}{15}\)

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