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29 tháng 4

Đề bài: \(\frac78+4\frac12:x=\frac{13}{40}\)

- Để giải phép tính, chúng ta sẽ thực hiện các bước sau:

  1. Chuyển đổi hỗn số thành phân số: \(4 \frac{1}{2} = \frac{9}{2}\)
  2. Viết lại phép tính: \(\frac{7}{8} + \frac{9}{2} : x = \frac{13}{40}\)
  3. Tìm \(\frac{9}{2} : x\)\(\frac{9}{2} : x = \frac{13}{40} - \frac{7}{8}\)
  4. Tính \(\frac{13}{40} - \frac{7}{8}\):
    • + Quy đồng mẫu số: \(\frac{13}{40} - \frac{7 \times 5}{8 \times 5} = \frac{13}{40} - \frac{35}{40}\)
    • + Tính hiệu: \(\frac{13 - 35}{40} = \frac{- 22}{40} = \frac{- 11}{20}\)
  5. Vậy, \(\frac{9}{2} : x = \frac{- 11}{20}\)
  6. Tìm x: \(x = \frac{9}{2} : \frac{- 11}{20}\)
  7. \(x = \frac{9}{2} \times \frac{- 20}{11}\)
  8. \(x = \frac{9 \times - 10}{11}\)
  9. \(x = \frac{- 90}{11}\)

Vậy kết quả phép tính trên là \(x = \frac{- 90}{11}\).

29 tháng 4

\(\frac78\) + 4\(\frac12\): \(x\) = \(\frac{13}{40}\)

\(\frac78\) + \(\frac92\) : \(x\) = \(\frac{13}{40}\)

\(\frac92\) : \(x\) = \(\frac{13}{40}\) - \(\frac78\)

\(\frac92\) : \(x\) = - \(\frac{11}{20}\)

\(x\) = \(\frac92\) : (- \(\frac{11}{20}\))

\(x\) = - \(\frac{90}{11}\)

Vậy \(x=-\frac{90}{11}\)

Ta có: \(C=5\dfrac{9}{10}:\dfrac{3}{2}-\left(2\dfrac{1}{3}\cdot4\dfrac{1}{2}-2\cdot2\dfrac{1}{3}\right):\dfrac{7}{4}\)

\(=\dfrac{59}{10}\cdot\dfrac{2}{3}-\left(\dfrac{7}{3}\cdot\dfrac{9}{2}-2\cdot\dfrac{7}{3}\right):\dfrac{7}{4}\)

\(=\dfrac{59}{15}-\left(\dfrac{7}{3}\cdot\dfrac{5}{2}\right):\dfrac{7}{4}\)

\(=\dfrac{59}{15}-\dfrac{35}{6}\cdot\dfrac{4}{7}\)

\(=\dfrac{59}{15}-\dfrac{10}{3}\)

\(=\dfrac{3}{5}\)

8 tháng 8 2020

Bài 1 :

\(a)\frac{-17}{30}-\frac{11}{-15}+\left(-\frac{7}{12}\right)\)

\(=\frac{1}{6}+\left(-\frac{7}{12}\right)\)

\(=-\frac{5}{12}\)

\(b)-\frac{5}{9}+\frac{5}{9}:\left(1\frac{2}{3}-2\frac{1}{12}\right)\)

\(=-\frac{5}{9}+\frac{5}{9}:\left(\frac{5}{3}-\frac{25}{12}\right)\)

\(=-\frac{5}{9}+\frac{5}{9}:\left(-\frac{5}{12}\right)\)

\(=-\frac{5}{9}+\left(-\frac{2}{3}\right)\)

\(=-\frac{1}{9}\)

\(c)-\frac{7}{25}\times\frac{11}{13}+\left(-\frac{7}{25}\right)\times\frac{2}{13}-\frac{18}{25}\)

\(=-\frac{77}{325}+\left(-\frac{14}{325}\right)-\frac{18}{25}\)

\(=-\frac{7}{25}-\frac{18}{25}\)

\(=-1\)

28 tháng 2 2018

a) \(x=\dfrac{1}{4}+\dfrac{2}{13}\)

\(x=\dfrac{13}{52}+\dfrac{8}{52}\)

\(x=\dfrac{21}{52}\)

b) \(\dfrac{x}{3}=\dfrac{2}{3}+\dfrac{-1}{7}\)

\(\dfrac{x}{3}=\dfrac{14}{21}+\dfrac{-3}{21}\)

\(\dfrac{x}{3}=\dfrac{11}{21}\)

\(x=\dfrac{11.3}{21}=\dfrac{33}{21}\)

\(x=\dfrac{11}{7}\)

c) \(\dfrac{-8}{3}+\dfrac{1}{3}< x< \dfrac{-2}{7}+\dfrac{-5}{7}\)

\(\dfrac{-17}{7}< x< -1\)

\(-17< x< -7\)

\(x\in\left\{-16;-15,....;-6\right\}\)

d) \(\dfrac{1}{6}+\dfrac{2}{5}\)

\(=\dfrac{5}{30}+\dfrac{12}{30}\)

\(=\dfrac{17}{30}\)

e) \(\dfrac{3}{5}+\dfrac{-7}{4}\)

\(=\dfrac{12}{20}+\dfrac{-35}{20}\)

\(=\dfrac{-23}{20}\)

f) \(\dfrac{4}{13}+\dfrac{-12}{30}\)

\(=\dfrac{4}{13}+\dfrac{-2}{5}\)

\(=\dfrac{20}{65}+\dfrac{-26}{65}\)

\(=\dfrac{-6}{65}\)

g) \(\dfrac{-3}{29}+\dfrac{16}{58}\)

\(=\dfrac{-6}{58}+\dfrac{16}{58}\)

\(=\dfrac{10}{58}\)

h) \(\dfrac{8}{40}+\dfrac{-36}{45}\)

\(=\dfrac{1}{5}+\dfrac{-4}{5}\)

\(=\dfrac{-3}{5}\)

j) \(\dfrac{-8}{18}+\dfrac{15}{27}\)

\(=\dfrac{-2}{9}+\dfrac{5}{9}\)

\(=\dfrac{3}{9}\)

\(=\dfrac{1}{3}\)

29 tháng 9 2018

đáp án:2520/6615 rút gọn 6/143

29 tháng 9 2018

\(1\frac{1}{3}\times1\frac{1}{4}\times1\frac{1}{5}\times...\times1\frac{1}{8}\)

\(=\frac{4}{3}\times\frac{5}{4}\times\frac{6}{5}\times...\times\frac{9}{8}\)

\(=\frac{9}{3}\)

27 tháng 7 2023

\(\dfrac{3\dfrac{1}{3}+\dfrac{1}{5}+2\dfrac{7}{15}}{\left(\dfrac{3}{10}+\dfrac{1}{4}+\dfrac{7}{20}\right).\dfrac{5}{6}}=\dfrac{\dfrac{10}{3}+\dfrac{1}{5}+\dfrac{37}{15}}{\left(\dfrac{6}{20}+\dfrac{5}{20}+\dfrac{7}{20}\right).\dfrac{5}{6}}\)

\(=\dfrac{\dfrac{50}{15}+\dfrac{3}{15}+\dfrac{37}{15}}{\dfrac{18}{20}.\dfrac{5}{6}}=\dfrac{6}{\dfrac{3}{4}}=\dfrac{6.4}{3}=8\)