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\(\frac{8}{11}+\frac{8}{33}\times\frac{3}{4}\)
\(=\frac{8}{11}+\frac{2}{11}\)
\(=\frac{8+2}{11}\)
\(=\frac{10}{11}\)
\(\frac{8}{11}+\frac{8}{33}\cdot\frac{3}{4}=\frac{8}{11}+\frac{8\cdot3}{33\cdot4}=\frac{8}{11}+\frac{2}{11}=\frac{10}{11}\)
\(\frac{7}{9}.\frac{3}{4}:\frac{5}{8}=\frac{7}{12}:\frac{5}{8}=\frac{7}{12}.\frac{8}{5}=\frac{14}{15}\)
kết quả = \(\frac{269}{210}\)nha bạn
ai tốt bụng thì tk cho mk , mk đg âm điểm đây huhu
Ta có: \(\frac{2}{1.2}+\frac{2}{2.3}+\frac{2}{3.4}+...+\frac{2}{18.19}+\frac{2}{19.20}=2.\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{18.19}+\frac{1}{19.20}\right)\)
\(=2.\left(\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{18}-\frac{1}{19}+\frac{1}{19}-\frac{1}{20}\right)\)
\(=2.\left(1-\frac{1}{20}\right)=\frac{2.19}{20}=\frac{19}{10}\)
\(\frac{2}{1\times2}+\frac{2}{2\times3}+......+\frac{2}{19\times20}\)
\(=2\left(\frac{1}{1\times2}+\frac{1}{2\times3}+.......+\frac{1}{19\times20}\right)\)
\(=2\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+........+\frac{1}{19}-\frac{1}{20}\right)\)
\(=2\left(1-\frac{1}{20}\right)=2.\frac{19}{20}=\frac{19}{10}\)
\(x=\frac{1}{2}+\frac{3}{4}=\frac{2}{4}+\frac{3}{4}=\frac{5}{4}\)
\(x-\frac{3}{4}=\frac{1}{2}\)
\(x=\frac{1}{2}+\frac{3}{4}\)
\(x=\frac{2}{4}+\frac{3}{4}\)
\(x=\frac{5}{4}\)