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\(\dfrac{5}{3}\cdot\dfrac{7}{25}+\dfrac{5}{3}\cdot\dfrac{21}{25}-\dfrac{5}{3}\cdot\dfrac{7}{25}\)
\(=\dfrac{5}{3}\cdot\left(\dfrac{7.}{25}+\dfrac{21}{25}-\dfrac{7}{25}\right)\)
\(=\dfrac{5}{3}\cdot\dfrac{21}{25}=\dfrac{7}{5}\)
b) \(250\%+19\dfrac{3}{11}\cdot\dfrac{7}{26}-6\dfrac{3}{11}\cdot\dfrac{7}{26}\)
\(=\dfrac{5}{2}+\dfrac{212}{11}\cdot\dfrac{7}{26}-\dfrac{69}{11}\cdot\dfrac{7}{26}\)
\(=\dfrac{7}{26}\cdot\left(\dfrac{212}{11}-\dfrac{69}{11}\right)+\dfrac{5}{2}\)
\(=\dfrac{7}{26}\cdot13+\dfrac{5}{2}\)
\(=\dfrac{7}{2}+\dfrac{5}{2}\)
\(=\dfrac{12}{2}=6\)
g: \(=\dfrac{-3}{4}-\dfrac{1}{4}+\dfrac{5}{7}+\dfrac{2}{7}+\dfrac{3}{5}=\dfrac{3}{5}\)
h: \(=\dfrac{7}{19}\left(\dfrac{8}{11}+\dfrac{3}{11}\right)-\dfrac{12}{19}=\dfrac{7}{19}-\dfrac{12}{19}=-\dfrac{5}{19}\)
i: \(=\dfrac{2013}{7}\left(19+\dfrac{5}{8}-26-\dfrac{5}{8}\right)=\dfrac{2013}{7}\cdot\left(-7\right)=-2013\)
Bài 1:
\(a,=\frac{2}{3}-\frac{16}{3}=\frac{-14}{3}\)
\(b,=\left(\frac{3}{7}+\frac{4}{7}\right)+\left(-\frac{6}{19}+\frac{-13}{19}\right)=1-1=0\)
\(c,=\frac{3}{5}.\left(\frac{8}{9}-\frac{7}{9}+\frac{26}{9}\right)=\frac{3}{5}.3=\frac{9}{5}\)
a,\(\dfrac{1}{2}\).\(\dfrac{4}{3}\)-\(\dfrac{20}{3}\).\(\dfrac{4}{5}\)=\(\dfrac{2}{3}\)-\(\dfrac{16}{3}\)=-\(\dfrac{14}{3}\)
a: \(=\dfrac{8}{9}\cdot\dfrac{9}{4}\cdot\dfrac{12}{19}\cdot\dfrac{19}{24}=\dfrac{1}{2}\cdot2=1\)
b: \(=\dfrac{5}{16}\cdot\dfrac{17}{15}\cdot\dfrac{8}{17}=\dfrac{5}{16}\cdot\dfrac{8}{15}=\dfrac{40}{240}=\dfrac{1}{6}\)
c: \(=\dfrac{4}{13}\left(\dfrac{2}{7}+\dfrac{5}{7}\right)-\dfrac{3}{26}=\dfrac{4}{13}-\dfrac{3}{26}=\dfrac{5}{26}\)
c: \(=\dfrac{3}{4}\left(\dfrac{6}{11}+\dfrac{5}{11}\right)-\dfrac{1}{5}=\dfrac{3}{4}-\dfrac{1}{5}=\dfrac{11}{20}\)
\(-2\dfrac{1}{4}.\)\(\left(3\dfrac{5}{12}-1\dfrac{2}{9}\right)\)
=\(\dfrac{-9}{4}\).\(\left(\dfrac{41}{12}-\dfrac{11}{9}\right)\)
=\(\dfrac{-9}{4}.\dfrac{41}{12}-\dfrac{-9}{4}.\dfrac{11}{9}\)
=\(\dfrac{-123}{16}-\dfrac{-11}{4}\)
=\(\dfrac{-123}{16}-\dfrac{-44}{16}\)
=\(\dfrac{-79}{16}\)
\(\left(-25\%+0,75+\dfrac{7}{12}\right)\div\left(-2\dfrac{1}{8}\right)\)
=\(\left(\dfrac{-1}{4}+\dfrac{3}{4}+\dfrac{7}{12}\right)\div\left(\dfrac{-17}{8}\right)\)
=\(\left(\dfrac{-3}{12}+\dfrac{9}{12}+\dfrac{7}{12}\right).\dfrac{-8}{17}\)
=\(\dfrac{13}{12}.\dfrac{-8}{17}=\dfrac{-26}{51}\)
\(A=\dfrac{6}{19}.\dfrac{-7}{11}+\dfrac{6}{19}.\dfrac{-4}{11}+\dfrac{-13}{19}\)
\(A=\dfrac{6}{19}.\left(\dfrac{-7}{11}+\dfrac{-4}{11}\right)+\dfrac{-13}{19}\)
\(A=\dfrac{6}{19}.-1+\dfrac{-13}{19}=\dfrac{-6}{19}+\dfrac{-13}{19}=\dfrac{-19}{19}=-1\)
B=57.−413+57.73−513.37
B=57.−413+57.73− \(\dfrac{5}{7}.\dfrac{3}{13}\)3
7
\(B=\dfrac{5}{7}.\left(\dfrac{-4}{13}+\dfrac{7}{3}-\dfrac{3}{13}\right)\)
\(B=\dfrac{5}{7}.\dfrac{70}{39}=\dfrac{350}{273}\)
Câu B ko rõ lắm
\(B=\dfrac{5}{7}.\dfrac{-4}{13}+\dfrac{5}{7}.\dfrac{7}{3}-\dfrac{5}{13}.\dfrac{3}{7}\)
\(B=\dfrac{5}{7}.\dfrac{-4}{13}+\dfrac{5}{7}.\dfrac{7}{3}-\dfrac{5}{7}.\dfrac{3}{13}\)
Rồi tiếp 2 câu rõ
A = 6/19 . -7/11 + 6/19 . -4/11 + -13/19
A = 6/19 . [-7/11 + (-4/11)] + (-13/19)
A = 6/19 . -11/11 + (-13/19)
A = 6/19 . (-1) + (-13/19)
A = -6/19 + (-13/19)
A = -19/19
A = -1
Vậy A = -1
\(\dfrac{26}{19}.\dfrac{4}{25}+\dfrac{7}{5}.\dfrac{3}{5}-\dfrac{4}{25}.\dfrac{7}{19}=\dfrac{104}{475}+\dfrac{7}{5}.\dfrac{3}{5}-\dfrac{4}{25}.\dfrac{7}{19}=\dfrac{104}{475}+\dfrac{21}{25}-\dfrac{4}{25}.\dfrac{7}{19}=\dfrac{503}{475}-\dfrac{4}{25}.\dfrac{7}{19}=\dfrac{503}{475}-\dfrac{28}{475}=\dfrac{475}{475}=1\)
\(\dfrac{26}{19}\cdot\dfrac{4}{25}+\dfrac{7}{5}\cdot\dfrac{3}{5}-\dfrac{4}{25}\cdot\dfrac{7}{19}=\dfrac{4}{25}\cdot\left(\dfrac{26}{19}-\dfrac{7}{19}\right)+\dfrac{7}{5}\cdot\dfrac{3}{5}=\dfrac{4}{25}\cdot1+\dfrac{21}{25}=\dfrac{4}{25}+\dfrac{21}{25}=\dfrac{25}{25}=1\)