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Vì \(\frac{1}{6}< 1\) mà \(\frac{169}{98}>1\) \(\Rightarrow x=1\)
nhớ k cho mik nha
\(\frac{22}{77}+\frac{56}{98}+\frac{25}{105}\)
\(\frac{2}{7}+\frac{4}{7}+\frac{5}{21}\)
\(\frac{23}{21}\)
a) \(\frac{3}{5}\times y+\frac{1}{2}:\frac{5}{3}-\frac{5}{4}=\frac{1}{2}\times\frac{1}{3}\)
\(\Rightarrow\frac{3}{5}\times y+\frac{3}{10}-\frac{5}{4}=\frac{1}{6}\)
\(\Rightarrow\frac{3}{5}\times y+\left(-\frac{19}{20}\right)=\frac{1}{6}\)
\(\Rightarrow\frac{3}{5}\times y=\frac{67}{60}\)
\(\Rightarrow y=\frac{67}{36}\)
b) \(\frac{4}{5}:y+\frac{1}{4}\times\frac{1}{6}-\frac{1}{2}=\frac{1}{3}\times\frac{5}{2}\)
\(\Rightarrow\frac{4}{5}:y+\frac{1}{24}-\frac{1}{2}=\frac{5}{6}\)
\(\Rightarrow\frac{4}{5}:y+\left(-\frac{11}{24}\right)=\frac{5}{6}\)
\(\Rightarrow\frac{4}{5}:y=\frac{5}{6}+\frac{11}{24}=\frac{31}{24}\)
\(\Rightarrow y=\frac{4}{5}:\frac{31}{24}=\frac{96}{155}\)
c) \(\frac{3}{5}\times y-\frac{4}{5}:3+\frac{1}{12}=\frac{3}{2}+\frac{1}{5}\)
\(\Rightarrow\frac{3}{5}\times y-\frac{4}{15}+\frac{1}{12}=\frac{17}{10}\)
\(\Rightarrow\frac{3}{5}\times y-\frac{4}{15}=\frac{97}{60}\)
\(\Rightarrow\frac{3}{5}\times y=\frac{113}{60}\)
\(\Rightarrow y=\frac{113}{36}\)
\(\frac{3}{5}+\frac{2}{7}=\frac{21}{35}+\frac{10}{35}=\frac{31}{35}\)
\(\frac{3}{9}-\frac{1}{5}=\frac{15}{45}-\frac{9}{45}=\frac{6}{45}\)
\(\frac{2}{5}\times\frac{3}{7}=\frac{6}{35}\)
\(\frac{4}{9}:\frac{2}{5}=\frac{4}{9}\times\frac{5}{2}=\frac{20}{18}\)
Trả lời
\(\frac{3}{5}+\frac{2}{7}=\frac{21}{35}+\frac{10}{35}=\frac{31}{35}\)
\(\frac{3}{9}-\frac{1}{5}=\frac{15}{45}-\frac{9}{45}=\frac{6}{45}=\frac{2}{15}\)
\(\frac{2}{5}\times\frac{3}{7}=\frac{6}{35}\)
\(\frac{4}{9}:\frac{2}{5}=\frac{4}{9}\times\frac{5}{2}=\frac{20}{18}=\frac{10}{9}\)
Study well
4 x 4 = 16
4 x 1 = 4
4 x 5 = 20
4 x 8 = 32
4 x 9 = 36
9 x 9 = 81
\(\left(1-\frac{1}{2}\right)\left(1-\frac{1}{3}\right)\left(1-\frac{1}{4}\right).....\left(1-\frac{1}{100}\right).200x=4036\)
\(\Leftrightarrow\frac{1}{2}.\frac{2}{3}.\frac{3}{4}.....\frac{99}{100}.200x=4036\)
\(\Leftrightarrow\frac{1.2.3...99}{2.3.4....100}.200x=4036\)
\(\Leftrightarrow\frac{1}{100}.200x=4036\)
\(\Leftrightarrow\frac{1}{100}.200x=4036\)
\(\Leftrightarrow2x=4036\)
\(\Leftrightarrow x=4036:2=2018\)
\(\left(1-\frac{1}{2}\right)\times\left(1-\frac{1}{3}\right)\times...\times\left(1-\frac{1}{100}\right)\times200\times x=4036\)
=> \(\frac{1}{2}\times\frac{2}{3}\times...\times\frac{99}{100}\times200\times x=4036\)
=> \(\frac{1\times2\times...\times99}{2\times3\times...\times100}\times200\times x=4036\)
\(\Rightarrow\frac{1}{100}\times200\times x=4036\)
\(\Rightarrow2\times x=4036\)
=> x = 2018
\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{98.99}+\frac{1}{99.100}\)
\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{99}-\frac{1}{100}\)
\(=1-\frac{1}{100}\)
\(=\frac{99}{100}\)
\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{98}-\frac{1}{99}+\frac{1}{99}-\frac{1}{100}\)
\(=1-\frac{1}{100}\)
\(=\frac{99}{100}\)
\(a,\frac{2001}{2002}.\frac{5}{7}.\frac{2002}{5}.\frac{7}{2001}=\left(\frac{2001}{2002}.\frac{7}{2001}\right).\left(\frac{5}{7}.\frac{2002}{5}\right)\)
\(=\frac{7}{2002}.\frac{2002}{7}=1\)
\(b,\frac{5}{7}.\frac{7}{9}.\frac{9}{11}.\frac{11}{13}=\left(\frac{5}{7}.\frac{7}{9}\right).\left(\frac{9}{11}.\frac{11}{13}\right)=\frac{5}{9}.\frac{9}{13}\)
\(=\frac{5}{13}\)
Mình làm cách lớp 6 nha bạn, cách lớp 4 mình không biết.
\(\frac{1}{2}.x+\frac{1}{5}.x=\frac{2}{5}\)
\(\Rightarrow x.\left(\frac{1}{2}+\frac{1}{5}\right)=\frac{2}{5}\)
\(\Rightarrow x.\frac{7}{10}=\frac{2}{5}\)
Giờ thành tìm x rồi!
\(x=\frac{7.5}{2.10}\)
\(x=1\frac{3}{4}\)
Xong!
\(\frac{1}{2}\times x+\frac{1}{5}\times x=\frac{2}{5}\)
\(x\times\left(\frac{1}{2}+\frac{1}{5}\right)=\frac{2}{5}\)
\(x\times\frac{7}{10}=\frac{2}{5}\)
\(x=\frac{2}{5}:\frac{7}{10}\)
\(x=\frac{4}{7}\)