Tính:
E=\(\frac{\frac{6}{7}-\frac{6}{9}+\frac{6}{11}-\frac{6}{13}}{\frac{8}{7}+\frac{8}{11}-\frac{8}{9}-\frac{8}{13}}\)
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đặt 6 ở tử làm thừa số chung và 8 ở mẫu làm thừa số chung.rút gọn ta được kq là 6/8=3/4
\(\frac{\frac{6}{7}-\frac{6}{9}+\frac{6}{11}-\frac{6}{13}}{\frac{8}{7}-\frac{8}{9}+\frac{8}{11}-\frac{8}{13}}\)
=\(\frac{6.\left(\frac{1}{7}-\frac{1}{9}+\frac{1}{11}-\frac{1}{13}\right)}{8.\left(\frac{1}{7}-\frac{1}{9}+\frac{1}{11}-\frac{1}{13}\right)}\)
=\(\frac{6}{8}\)
=\(\frac{3}{4}\)
Ta có :
\(P=\frac{\frac{6}{8}+\frac{6}{10}+\frac{6}{14}+\frac{6}{26}}{\frac{11}{4}+\frac{11}{5}+\frac{11}{7}+\frac{11}{13}}\)
\(\Rightarrow P=\frac{\frac{3}{4}+\frac{3}{5}+\frac{3}{7}+\frac{3}{13}}{11\left(\frac{1}{4}+\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right)}\)
\(\Rightarrow P=\frac{3\left(\frac{1}{4}+\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right)}{11\left(\frac{1}{4}+\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right)}\)
\(\Rightarrow P=\frac{3}{11}\)
Vậy \(P=\frac{3}{11}\)
\(P=\frac{\frac{3}{4}-\frac{3}{5}+\frac{3}{7}+\frac{3}{13}}{\frac{11}{4}-\frac{11}{5}+\frac{11}{7}+\frac{11}{13}}=\frac{3}{11}\)
đề bài của bn sai nên mk sửa luôn nha
Bài 1:
a) Ta có: \(\frac{8}{40}+\frac{-4}{20}-\frac{3}{5}\)
\(=\frac{1}{5}+\frac{-1}{5}-\frac{3}{5}\)
\(=\frac{-3}{5}\)
b) Ta có: \(\frac{-7}{12}+\frac{-2}{12}-\frac{-3}{36}\)
\(=\frac{-7}{12}+\frac{-2}{12}-\frac{-1}{12}\)
\(=\frac{-9+1}{12}=\frac{-8}{12}=\frac{-2}{3}\)
c) Ta có: \(\left(\frac{1}{6}+\frac{-4}{13}\right)-\left(-\frac{17}{6}-\frac{30}{13}\right)\)
\(=\frac{1}{6}+\frac{-4}{13}+\frac{17}{6}+\frac{30}{13}\)
\(=3+2=5\)
d) Ta có: \(-\frac{-5}{4}+\frac{7}{4}-\frac{-11}{7}+\frac{2}{7}\)
\(=\frac{5}{4}+\frac{7}{4}+\frac{11}{7}+\frac{2}{7}\)
\(=3+\frac{13}{7}=\frac{21}{7}+\frac{13}{7}=\frac{34}{7}\)
e) Ta có: \(-\frac{1}{8}+\frac{-7}{9}+\frac{-7}{8}+\frac{6}{7}+\frac{2}{14}\)
\(=-1+1+\frac{-7}{9}\)
\(=-\frac{7}{9}\)
f) Ta có: \(\frac{-2}{9}-\frac{11}{-9}+\frac{5}{7}-\frac{-6}{-7}\)
\(=\frac{-2-\left(-11\right)}{9}+\frac{5-6}{7}\)
\(=1+\frac{-1}{7}=\frac{7}{7}+\frac{-1}{7}=\frac{6}{7}\)
Tính :
a) \(\frac{1}{6}.\frac{9}{-8}.\left(-\frac{12}{11}\right)=\frac{1.9.\left(-12\right)}{6.\left(-8\right).11}=\frac{1.3.3}{2.2.11}=\frac{9}{44}\)
b) \(\frac{1}{8}.\frac{-3}{7}+\frac{1}{8}.\frac{-4}{7}\)
\(=\frac{1}{8}.\left(-\frac{3}{7}+\frac{-4}{7}\right)\)
\(=\frac{1}{8}.\frac{-7}{7}=\frac{1}{8}.\left(-1\right)\)
\(=-\frac{1}{8}\)
c) \(\frac{7}{13}.\frac{3}{-5}+\frac{6}{13}.\frac{-3}{5}\)
\(=-\frac{3}{5}.\left(\frac{7}{13}+\frac{6}{13}\right)\)
\(=-\frac{3}{5}.\frac{13}{13}=-\frac{3}{5}.1\)
\(=-\frac{3}{5}\)
a, \(\frac{1}{6}.\frac{9}{-8}.\frac{-12}{11}\)
\(\Rightarrow\frac{9}{8}.\frac{2}{11}\)
\(\Rightarrow\frac{9}{4}.\frac{1}{11}\)
\(\Rightarrow\frac{9}{44}\)
b,\(\frac{1}{8}.\frac{-3}{7}+\frac{1}{8}.\frac{-4}{7}\)
\(\Rightarrow\frac{-3}{56}-\frac{1}{2}.\frac{1}{7}\)
\(\Rightarrow\frac{-3}{56}-\frac{1}{2}.\frac{1}{7}\)
\(\Rightarrow\frac{-3}{56}-\frac{1}{14}\)
\(\Rightarrow\frac{-1}{8}\)
c,\(\frac{7}{13}.\frac{3}{-5}+\frac{6}{13}.\frac{-3}{5}\)
\(\Rightarrow\frac{-21}{65}-\frac{18}{65}\)
\(\Rightarrow\frac{-3}{5}\)
\(E=\frac{6\left(\frac{1}{7}-\frac{1}{9}+\frac{1}{11}-\frac{1}{13}\right)}{8\left(\frac{1}{7}-\frac{1}{9}+\frac{1}{11}-\frac{1}{13}\right)}=\frac{6}{8}=\frac{3}{4}\)