Question

Bài 2. Tìm x:

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

 

Answer 1

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

=>\(\dfrac{2}{7}:x=-1-\dfrac{5}{7}=-\dfrac{12}{7}\)

=>\(x=-\dfrac{2}{7}:\dfrac{12}{7}=-\dfrac{2}{7}\cdot\dfrac{7}{12}=-\dfrac{2}{12}=-\dfrac{1}{6}\)

Answer 2

\(\dfrac{5}{7}+\dfrac{2}{7}:x=\left(-1\right)\)

\(1:x=\left(-1\right)\)

      \(x=1:\left(-1\right)\Leftrightarrow x=-1\)

Answer 3

\(\dfrac{5}{7}+\dfrac{2}{7}:x=\left(-1\right)\)
\(\dfrac{2}{7}:x=-1-\dfrac{5}{7}\)
\(\dfrac{2}{7}:x=\dfrac{-7}{7}-\dfrac{5}{7}\)
\(\dfrac{2}{7}:x=\dfrac{-12}{7}\)
\(x=\dfrac{2}{7}:\dfrac{-12}{7}\)
\(x=\dfrac{2}{7}.\dfrac{-7}{12}\)
\(x=\dfrac{-1}{6}\)
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