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Đặt tử = A.Ta có:
\(A=0,75+\frac{3}{7}+\frac{3}{11}=\frac{3}{4}+\frac{3}{7}+\frac{3}{11}\)
\(=3\left(\frac{1}{4}+\frac{1}{7}+\frac{1}{11}\right)\)
Đặt mẫu = B.Ta có:
\(B=2\frac{1}{4}+\frac{9}{11}+\frac{9}{7}=\frac{9}{4}+\frac{9}{11}+\frac{9}{7}\)
\(=9\left(\frac{1}{4}+\frac{1}{11}+\frac{1}{7}\right)\)
Thay A và B vào ta đc: \(\frac{A}{B}=\frac{3\left(\frac{1}{4}+\frac{1}{7}+\frac{1}{11}\right)}{9\left(\frac{1}{4}+\frac{1}{11}+\frac{1}{7}\right)}=\frac{3}{9}=\frac{1}{3}\)
â, -4/9(7/15+8/15)=-4/9
b,-5/4(16/25+9/25)=-5/4
,.....
dài quá mik làm ko hết
hok tốt
\(A=21\frac{4}{11}-\left(1\frac{3}{5}+7\frac{4}{11}\right)\)
\(A=\frac{235}{11}-\left(\frac{8}{5}+\frac{81}{11}\right)\)
\(A=\left(\frac{235}{11}-\frac{81}{11}\right)+\frac{8}{5}\)
\(A=\frac{154}{11}+\frac{8}{5}\)
\(\Rightarrow A=\frac{78}{5}\)
\(B=\left(7\frac{8}{9}+2\frac{3}{13}\right)-\left(4\frac{8}{9}-7\frac{10}{13}\right)\)
\(B=\left(\frac{71}{9}+\frac{29}{13}\right)-\left(\frac{44}{9}-\frac{101}{13}\right)\)
\(B=\left(\frac{71}{9}-\frac{44}{9}\right)+\left(\frac{29}{13}-\frac{101}{13}\right)\)
\(B=\frac{27}{9}+\frac{-72}{13}\)
\(B=3+\frac{-72}{13}\)
\(\Rightarrow B=\frac{-33}{13}\)
P/s: Hoq chắc :v
g) \(6\frac{4}{5}-\left(1\frac{2}{3}+3\frac{4}{5}\right)\)
\(=6\frac{4}{5}-1\frac{2}{3}-3\frac{4}{5}\)
\(=\left(6\frac{4}{5}-3\frac{4}{5}\right)-1\frac{2}{3}\)
\(=\left(6+\frac{4}{5}-3-\frac{4}{5}\right)-1\frac{2}{3}\)
\(=3-\frac{5}{3}=\frac{9}{3}-\frac{5}{3}=\frac{4}{3}\)
h) \(7\frac{5}{9}-\left(2\frac{3}{4}+3\frac{5}{9}\right)\)
\(=7\frac{5}{9}-2\frac{3}{4}-3\frac{5}{9}\)
\(=\left(7\frac{5}{9}-3\frac{5}{9}\right)-2\frac{3}{4}\)
\(=\left(7+\frac{5}{9}-3-\frac{5}{9}\right)-2\frac{3}{4}\)
\(=4-\frac{11}{4}=\frac{16}{4}-\frac{11}{4}=\frac{5}{4}\)
i) \(6\frac{5}{7}-\left(1\frac{3}{4}+2\frac{5}{7}\right)\)
\(=6\frac{5}{7}-1\frac{3}{4}-2\frac{5}{7}\)
\(=\left(6\frac{5}{7}-2\frac{5}{7}\right)-1\frac{3}{4}\)
\(=\left(6+\frac{5}{7}-2-\frac{5}{7}\right)-\frac{7}{4}\)
\(=4-\frac{7}{4}=\frac{16}{4}-\frac{7}{4}=\frac{9}{4}\)
k) \(7\frac{5}{11}-\left(2\frac{3}{7}+3\frac{5}{11}\right)\)
\(=7\frac{5}{11}-2\frac{3}{7}-3\frac{5}{11}\)
\(=\left(7\frac{5}{11}-3\frac{5}{11}\right)-2\frac{3}{7}\)
\(=4-\frac{17}{7}=\frac{28}{7}-\frac{17}{7}=\frac{11}{7}\)
g) Ta có: \(6\frac{4}{5}-\left(1\frac{2}{3}+3\frac{4}{5}\right)\)
\(=\frac{34}{5}-\left(\frac{5}{3}+\frac{19}{5}\right)\)
\(=\frac{34}{5}-\frac{5}{3}-\frac{19}{5}\)
\(=3-\frac{5}{3}=\frac{9}{3}-\frac{5}{3}=\frac{4}{3}\)
h) Ta có: \(7\frac{5}{9}-\left(2\frac{3}{4}+3\frac{5}{9}\right)\)
\(=\frac{68}{9}-\frac{11}{4}-\frac{32}{9}\)
\(=4-\frac{11}{4}=\frac{16}{4}-\frac{11}{4}=\frac{5}{4}\)
i) Ta có: \(6\frac{5}{7}-\left(1\frac{3}{4}+2\frac{5}{7}\right)\)
\(=6+\frac{5}{7}-1-\frac{3}{4}-2-\frac{5}{7}\)
\(=3-\frac{3}{4}=\frac{9}{4}\)
k) Ta có: \(7\frac{5}{11}-\left(2\frac{3}{7}+3\frac{5}{11}\right)\)
\(=7+\frac{5}{11}-2-\frac{3}{7}-3-\frac{5}{11}\)
\(=2-\frac{3}{7}=\frac{11}{7}\)
\(\frac{\frac{2}{3}+\frac{2}{5}-\frac{2}{9}}{\frac{4}{3}+\frac{4}{5}-\frac{4}{9}}\) _ \(\frac{3-\frac{3}{11}-\frac{3}{17}}{5-\frac{5}{11}-\frac{5}{17}}\)
=\(\frac{2\left(\frac{1}{3}+\frac{1}{5}-\frac{1}{9}\right)}{4\left(\frac{1}{3}+\frac{1}{5}-\frac{1}{9}\right)}\)_ \(\frac{3\left(1-\frac{1}{11}-\frac{1}{17}\right)}{5\left(1-\frac{1}{11}-\frac{1}{17}\right)}\)= \(\frac{2}{4}-\frac{3}{5}\)= \(\frac{-1}{10}\)
b,\(-\frac{5}{7}.\frac{4}{13}+-\frac{5}{7}.\frac{9}{13}+-\frac{2}{7}\)
\(=-\frac{5}{7}.\left(\frac{4}{13}+\frac{9}{13}\right)+-\frac{2}{7}\)
\(=-\frac{5}{7}+-\frac{2}{7}=-1\)
học tốt nha e!
a, \(\frac{2}{3}+\left(\frac{3}{11}+-\frac{2}{5}\right)+-\frac{2}{5}\)
\(=\frac{2}{3}+(-\frac{22}{55}+-\frac{2}{5})\)
\(=\frac{2}{3}+-\frac{44}{115}=....??\)
\(\frac{-3}{4}.\frac{2}{11}+\frac{3}{4}.\frac{9}{11}+2\frac{3}{4}\)
\(=\frac{3}{4}.\frac{-2}{11}+\frac{3}{4}.\frac{9}{11}+\frac{3}{4}+2\)
\(=\frac{3}{4}\left(-\frac{2}{11}+\frac{9}{11}+1\right)+2\)
\(=\frac{3}{4}.\frac{18}{11}+2\)
\(=\frac{27}{22}+2\)
\(=\frac{71}{22}\)
Study well ! >_<
=\(\frac{71}{22}\).HỌKKKKKKKKKKK