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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) $\frac{-11}{12}.y+0,25=\frac{5}{6}$

đỗ thị lan anh · Accepted Answer

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}$$\frac{7}{5}.y=\frac{-43}{35}$ Câu trả lời: a) $\frac{-3}{5}.y=\frac{21}{10}$          $y=\frac{21}{10}:\frac{-3}{5}$         $y=\frac{-7}{2}$vậy $y=\frac{-7}{2}$b) $y:\frac{3}{8}=-1\frac{31}{33}$  $y:\frac{3}{8}=\frac{-64}{33}$$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}$

đỗ thị lan anh · Answer

$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}$$y=\frac{-7}{11}$vậy $y=\frac{-7}{11}$Câu trả lời: $y=\frac{-43}{35}:\frac{7}{5}$$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 $y=\frac{-7}{11}$

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