Cho biết x thỏa mãn \(\left(1\dfrac{1}{4}x-\dfrac{1}{5}\right).1\dfrac{2}{3}=5,55\). Giá trị của x là
\(x=\dfrac{353}{125}\) \(x=\dfrac{14}{5}\) \(x=\dfrac{12}{5}\) \(x=\dfrac{13}{10}\) Hướng dẫn giải:\(\left(1\dfrac{1}{4}x-\dfrac{1}{5}\right).1\dfrac{2}{3}=5,55\)
\(\Leftrightarrow1\dfrac{1}{4}x-\dfrac{1}{5}=5,55:1\dfrac{2}{3}\)
\(\Leftrightarrow\dfrac{5}{4}x-\dfrac{1}{5}=\dfrac{111}{20}:\dfrac{5}{3}\)
\(\Leftrightarrow\dfrac{5}{4}x-\dfrac{1}{5}=\dfrac{111}{20}:\dfrac{5}{3}\)
\(\Leftrightarrow\dfrac{5}{4}x-\dfrac{1}{5}=\dfrac{333}{100}\)
\(\Leftrightarrow\dfrac{5}{4}x=\dfrac{333}{100}+\dfrac{1}{5}\)
\(\Leftrightarrow\dfrac{5}{4}x=\dfrac{353}{100}\)
\(\Leftrightarrow x=\dfrac{353}{125}\)