Question

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Answer 1

Bài 1:
a) $(3 + \frac{1}{3}) x + 16 + \frac{3}{4} = - 13, 25 \Rightarrow \frac{10}{3} x + \frac{67}{4} = - \frac{53}{4} (d o 13, 25 = - \frac{1325}{100} = - \frac{53}{4})$
= $\frac{10}{3} x = - \frac{53}{4} - \frac{67}{4} \Rightarrow \frac{10}{3} x = - \frac{120}{4} = - 30 \Rightarrow x = - 30 : \frac{10}{3} = - 30 \times \frac{3}{10} \Rightarrow x = - 9$
b) $\frac{2}{5} + \frac{3}{5} : (\frac{3}{5} + \frac{- 2}{3}) - 3 \frac{1}{2}$ = $\frac{2}{5} + \frac{3}{5} : (\frac{9}{15} + \frac{- 10}{15}) - (3 + \frac{1}{2})$
= $\frac{2}{5} + \frac{3}{5} : \frac{- 1}{15} - 3 - \frac{1}{2}$ = $\frac{2}{5} + \frac{3}{5} \times \frac{15}{- 1} - 3 - \frac{1}{2}$
= $\frac{2}{5} - 9 - 3 - \frac{1}{2}$ = $\frac{2}{5} - 12 - \frac{1}{2}$ = $\frac{4}{10} - \frac{120}{10} - \frac{5}{10}$ = $\frac{- 121}{10}$
c) $(4 - \frac{5}{2}) : 3 + \frac{7}{36}$ = $(\frac{8}{2} - \frac{5}{2}) : 3 + \frac{7}{36}$ = $\frac{3}{2} \times \frac{1}{3} + \frac{7}{36}$
= $\frac{1}{2} + \frac{7}{36} = \frac{18}{36} + \frac{7}{36} = \frac{25}{36}$
d) $(2 + \frac{5}{6}) : 1 \frac{1}{5} + \frac{- 7}{12}$ = $(\frac{12}{6} + \frac{5}{6}) : (1 + \frac{1}{5}) + \frac{- 7}{12}$
= $\frac{17}{6} : (\frac{5}{5} + \frac{1}{5}) + \frac{- 7}{12}$ = $\frac{17}{6} : \frac{6}{5} + \frac{- 7}{12}$ = $\frac{17}{6} \times \frac{5}{6} + \frac{- 7}{12}$
= $\frac{85}{36} + \frac{- 7}{12} = \frac{85}{36} - \frac{21}{36} = \frac{64}{36} = \frac{16}{9}$
Bài 2:
a) $\frac{2}{3} + \frac{1}{3} : x = \frac{3}{5}$
=> $\frac{1}{3 x} = \frac{3}{5} - \frac{2}{3} = \frac{9}{15} - \frac{10}{15} = \frac{- 1}{15}$
=> $3 x = - 15 \Rightarrow x = \frac{- 15}{3} = - 5$
b) $8 \frac{2}{3} : x - 10 = - 8$ => $(8 + \frac{2}{3}) : x = - 8 + 10 = 2$
=> $(\frac{24}{3} + \frac{2}{3}) : x = 2$ => $\frac{22}{3 x} = 2$ => $6 x = 22$ => x = $\frac{22}{6} = \frac{11}{3}$
c) x + 30%x = -1.3
=> x + 0.3x = - 1,3
=> 1.3x = -1,3
=> x = $\frac{- 1, 3}{1, 3} = - 1$

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Answer 2

Bài 1:
a) $(3 + \frac{1}{3}) x + 16 + \frac{3}{4} = - 13, 25 \Rightarrow \frac{10}{3} x + \frac{67}{4} = - \frac{53}{4} (d o 13, 25 = - \frac{1325}{100} = - \frac{53}{4})$
= $\frac{10}{3} x = - \frac{53}{4} - \frac{67}{4} \Rightarrow \frac{10}{3} x = - \frac{120}{4} = - 30 \Rightarrow x = - 30 : \frac{10}{3} = - 30 \times \frac{3}{10} \Rightarrow x = - 9$
b) $\frac{2}{5} + \frac{3}{5} : (\frac{3}{5} + \frac{- 2}{3}) - 3 \frac{1}{2}$ = $\frac{2}{5} + \frac{3}{5} : (\frac{9}{15} + \frac{- 10}{15}) - (3 + \frac{1}{2})$
= $\frac{2}{5} + \frac{3}{5} : \frac{- 1}{15} - 3 - \frac{1}{2}$ = $\frac{2}{5} + \frac{3}{5} \times \frac{15}{- 1} - 3 - \frac{1}{2}$
= $\frac{2}{5} - 9 - 3 - \frac{1}{2}$ = $\frac{2}{5} - 12 - \frac{1}{2}$ = $\frac{4}{10} - \frac{120}{10} - \frac{5}{10}$ = $\frac{- 121}{10}$
c) $(4 - \frac{5}{2}) : 3 + \frac{7}{36}$ = $(\frac{8}{2} - \frac{5}{2}) : 3 + \frac{7}{36}$ = $\frac{3}{2} \times \frac{1}{3} + \frac{7}{36}$
= $\frac{1}{2} + \frac{7}{36} = \frac{18}{36} + \frac{7}{36} = \frac{25}{36}$
d) $(2 + \frac{5}{6}) : 1 \frac{1}{5} + \frac{- 7}{12}$ = $(\frac{12}{6} + \frac{5}{6}) : (1 + \frac{1}{5}) + \frac{- 7}{12}$
= $\frac{17}{6} : (\frac{5}{5} + \frac{1}{5}) + \frac{- 7}{12}$ = $\frac{17}{6} : \frac{6}{5} + \frac{- 7}{12}$ = $\frac{17}{6} \times \frac{5}{6} + \frac{- 7}{12}$
= $\frac{85}{36} + \frac{- 7}{12} = \frac{85}{36} - \frac{21}{36} = \frac{64}{36} = \frac{16}{9}$
Bài 2:
a) $\frac{2}{3} + \frac{1}{3} : x = \frac{3}{5}$
=> $\frac{1}{3 x} = \frac{3}{5} - \frac{2}{3} = \frac{9}{15} - \frac{10}{15} = \frac{- 1}{15}$
=> $3 x = - 15 \Rightarrow x = \frac{- 15}{3} = - 5$
b) $8 \frac{2}{3} : x - 10 = - 8$ => $(8 + \frac{2}{3}) : x = - 8 + 10 = 2$
=> $(\frac{24}{3} + \frac{2}{3}) : x = 2$ => $\frac{22}{3 x} = 2$ => $6 x = 22$ => x = $\frac{22}{6} = \frac{11}{3}$
c) x + 30%x = -1.3
=> x + 0.3x = - 1,3
=> 1.3x = -1,3
=> x = $\frac{- 1, 3}{1, 3} = - 1$

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