Question

Tìm x biết:

a) \(\frac{-3}{5}.y=\frac{21}{10}\)

b) \(y:\frac{3}{8}=-1\frac{31}{33}\)

c) \(1\frac{2}{5}.y+\frac{3}{7}=\frac{-4}{5}\)

d) \(\frac{-11}{12}.y+0,25=\frac{5}{6}\)

Answer 1

a) \(\frac{-3}{5}.y=\frac{21}{10}\)

          \(y=\frac{21}{10}:\frac{-3}{5}\)

         \(y=\frac{-7}{2}\)

vậy \(y=\frac{-7}{2}\)

b) \(y:\frac{3}{8}=-1\frac{31}{33}\)

  \(y:\frac{3}{8}=\frac{-64}{33}\)

\(y=\frac{-64}{33}.\frac{3}{8}\)

\(y=\frac{-8}{11}\)

vậy \(y=\frac{-8}{11}\)

c) \(1\frac{2}{5}.y+\frac{3}{7}=\frac{-4}{5}\)

\(\frac{7}{5}.y+\frac{3}{7}=\frac{-4}{5}\)

\(\frac{7}{5}.y=\frac{-4}{5}-\frac{3}{7}\)

\(\frac{7}{5}.y=\frac{-43}{35}\)

 

Answer 2

\(y=\frac{-43}{35}:\frac{7}{5}\)

\(y=\frac{-43}{49}\)

vậy \(y=\frac{-43}{49}\)

d) \(\frac{-11}{12}.y+0,25=\frac{5}{6}\)

\(\frac{-11}{12}.y=\frac{5}{6}-0,25\)

\(\frac{-11}{12}.y=\frac{7}{12}\)

\(y=\frac{7}{12}:\frac{-11}{12}\)

\(y=\frac{-7}{11}\)

vậy \(y=\frac{-7}{11}\)