C=\(\dfrac{7}{19}\times\dfrac{5}{8}\times\dfrac{-19}{7}\)
D=\(\dfrac{3}{7}\times\dfrac{9}{11}+\dfrac{3}{7}\times\dfrac{2}{11}\)
K
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VT
31 tháng 12 2022
\(C=\dfrac{4}{9}\times\dfrac{13}{17}+\dfrac{4}{17}\times\dfrac{4}{9}+\dfrac{2}{9}\\ =\dfrac{4}{9}\times\left(\dfrac{13}{17}+\dfrac{4}{17}\right)+\dfrac{2}{9}\\ =\dfrac{4}{9}\times1+\dfrac{2}{9}\\ =\dfrac{4}{9}+\dfrac{2}{9}\\ =\dfrac{6}{9}=\dfrac{2}{3}\)
\(D=\dfrac{8}{19}\times\dfrac{5}{11}+\dfrac{7}{11}\times\dfrac{8}{19}+\dfrac{12}{11}\times\dfrac{11}{19}\\ =\dfrac{8}{19}\times\left(\dfrac{5}{11}+\dfrac{7}{11}\right)+\dfrac{12}{11}\times\dfrac{11}{19}\\ =\dfrac{8}{19}\times\dfrac{12}{11}+\dfrac{12}{11}\times\dfrac{11}{19}\\ =\dfrac{12}{11}\times\left(\dfrac{8}{19}+\dfrac{11}{19}\right)\\ =\dfrac{12}{11}\times19\\ =\dfrac{12}{11}\)
31 tháng 12 2022
\(C=\dfrac{4}{9}\cdot\dfrac{13}{17}+\dfrac{4}{17}\cdot\dfrac{4}{9}+\dfrac{2}{9}\)
\(C=\dfrac{4}{9}\cdot\left(\dfrac{13}{17}+\dfrac{4}{17}\right)+\dfrac{2}{9}\)
\(C=\dfrac{4}{9}\cdot\dfrac{13+4}{17}+\dfrac{2}{9}\)
\(C=\dfrac{4}{9}\cdot\dfrac{17}{17}+\dfrac{9}{2}\)
\(C=\dfrac{4}{9}\cdot1+\dfrac{2}{9}\)
\(C=\dfrac{4}{9}+\dfrac{2}{9}\)
\(C=\dfrac{4+2}{9}\)
\(C=\dfrac{6}{9}\)
\(C=\dfrac{2}{3}\)
\(D=\dfrac{8}{19}\cdot\dfrac{5}{11}+\dfrac{7}{11}\cdot\dfrac{8}{19}+\dfrac{12}{11}\cdot\dfrac{11}{19}\)
\(D=\dfrac{8}{19}\cdot\left(\dfrac{5}{11}+\dfrac{7}{11}\right)+\dfrac{12}{11}\cdot\dfrac{11}{19}\)
\(D=\dfrac{8}{19}\cdot\dfrac{12}{11}+\dfrac{12}{11}\cdot\dfrac{11}{19}\)
\(D=\dfrac{12}{11}\cdot\left(\dfrac{8}{19}+\dfrac{11}{19}\right)\)
\(D=\dfrac{12}{11}\cdot\dfrac{19}{19}\)
\(D=\dfrac{12}{11}\cdot1\)
\(D=\dfrac{12}{11}\)
H9
HT.Phong (9A5)
CTVHS
24 tháng 8 2023
a) \(\dfrac{3}{5}\times\dfrac{17}{21}+\dfrac{2}{5}\times\dfrac{17}{21}\)
\(=\dfrac{17}{21}\times\left(\dfrac{3}{5}+\dfrac{2}{5}\right)\)
\(=\dfrac{17}{21}\times1\)
\(=\dfrac{17}{21}\)
b) \(\dfrac{11}{19}\times\dfrac{2}{7}+\dfrac{5}{7}\times\dfrac{11}{19}\)
\(=\dfrac{11}{19}\times\left(\dfrac{2}{7}+\dfrac{5}{7}\right)\)
\(=\dfrac{11}{19}\times1\)
\(=\dfrac{11}{19}\)
24 tháng 8 2023
a: =17/21(3/5+2/5)
=17/21*5/5
=17/21
b: =11/19(2/7+5/7)
=11/19*1
=11/19
MH
26 tháng 1 2022
\(A=\dfrac{-19}{9}.\dfrac{1}{2}-\dfrac{4}{11}.\dfrac{-11}{9}+\left(-\dfrac{2}{3}\right)=-\dfrac{23}{18}\)
\(B=\left(-\dfrac{15}{6}\right):\dfrac{-1}{2}+\dfrac{7}{-12}-\dfrac{1}{3}.\dfrac{-11}{2}=\dfrac{25}{4}\)
\(C=\dfrac{3}{4}.\left(-8\right)-\dfrac{1}{3}.\dfrac{-7}{2}-\dfrac{5}{18}=-\dfrac{46}{9}\)
26 tháng 1 2022
\(A=\dfrac{-19}{18}+\dfrac{4}{9}-\dfrac{2}{3}=\dfrac{-19}{18}+\dfrac{8}{18}-\dfrac{12}{18}=\dfrac{-23}{18}\)
\(B=\dfrac{-5}{2}\cdot\dfrac{-2}{1}-\dfrac{7}{12}+\dfrac{11}{6}=\dfrac{5\cdot12-7+22}{12}=\dfrac{75}{12}=\dfrac{25}{4}\)
GL
25 tháng 8 2023
a) \(\dfrac{3}{5}+\dfrac{7}{25}=\dfrac{15}{25}+\dfrac{7}{25}=\dfrac{15+7}{25}=\dfrac{22}{25}\)
b) \(\dfrac{8}{11}-\dfrac{19}{33}=\dfrac{24}{33}-\dfrac{19}{33}=\dfrac{24-19}{33}=\dfrac{5}{33}\)
c) \(\dfrac{16}{21}\times\dfrac{3}{5}=\dfrac{16\times3}{21\times5}=\dfrac{48}{105}=\dfrac{16}{35}\)
d) \(\dfrac{14}{41}\div\dfrac{7}{9}=\dfrac{14}{41}\times\dfrac{9}{7}=\dfrac{14\times9}{41\times7}=\dfrac{126}{287}=\dfrac{18}{41}\)
H
24 tháng 8 2023
a)
\(\dfrac{3}{5}\times\dfrac{7}{11}\times\dfrac{5}{3}\times11\\ =\left(\dfrac{3}{5}\times\dfrac{5}{3}\right)\times\left(\dfrac{7}{11}\times11\right)\\ =\dfrac{3\times5}{5\times3}\times\dfrac{7\times11}{11}\\ =1\times7\\ =7\)
b)
\(\dfrac{3}{8}\times\dfrac{2}{7}+\dfrac{5}{7}\times\dfrac{3}{8}\\ =\dfrac{3}{8}\times\left(\dfrac{2}{7}+\dfrac{5}{7}\right)\\ =\dfrac{3}{8}\times\dfrac{7}{7}\\ =\dfrac{3}{8}\times1=\dfrac{3}{8}\)
CT
1
13 tháng 3 2018
a, \(\dfrac{-4}{11}.\dfrac{7}{15}-\dfrac{4}{15}.\dfrac{8}{11}+\dfrac{-5}{11}\)
=\(\dfrac{-4}{11}.\dfrac{7}{15}+\dfrac{-4.8}{15.11}+\dfrac{-5}{11}\)
=\(\dfrac{-4}{11}.\dfrac{7}{15}+\dfrac{8}{15}.\dfrac{-4}{11}+\dfrac{-5}{11}\)
=\(\dfrac{-4}{11}.\left(\dfrac{7}{15}+\dfrac{8}{15}\right)+\dfrac{-5}{11}\)
=\(\dfrac{-4}{11}.1+\dfrac{-5}{11}\)
=\(\dfrac{-9}{11}\)
HQ
Hà Quang Minh
Giáo viên
27 tháng 11 2023
a) $\frac{7}{2} \times \frac{1}{6} = \frac{7}{{12}}$
b) $\frac{8}{{11}} \times 4 = \frac{{32}}{{11}}$
c) $\frac{8}{9}:\frac{2}{5} = \frac{8}{9} \times \frac{5}{2} = \frac{{40}}{{18}} = \frac{{20}}{9}$
d) $\frac{5}{8}:7 = \frac{5}{8} \times \frac{1}{7} = \frac{5}{{56}}$
HQ
Hà Quang Minh
Giáo viên
27 tháng 11 2023
a) $\frac{2}{5} \times \frac{3}{8} \times \frac{3}{4} = \frac{{2 \times 3 \times 3}}{{5 \times 8 \times 4}} = \frac{{18}}{{160}} = \frac{9}{{80}}$
b) $\frac{1}{3} \times \frac{1}{6} \times \frac{1}{9} = \frac{{1 \times 1 \times 1}}{{3 \times 6 \times 9}} = \frac{1}{{162}}$
c) $\frac{3}{4}:\frac{1}{5}:\frac{7}{8} = \frac{3}{4} \times \frac{5}{1} \times \frac{8}{7} = \frac{{3 \times 5 \times 8}}{{4 \times 1 \times 7}} = \frac{{120}}{{28}} = \frac{{30}}{7}$
d) $\frac{3}{5}:\frac{1}{5}:\frac{3}{8} = \frac{3}{5} \times \frac{5}{1} \times \frac{8}{3} = \frac{{3 \times 5 \times 8}}{{5 \times 1 \times 3}} = 8$
C)
`7/19xx5/8xx (-19)/7`
`=7/19xx (-19/7)xx5/8`
`= -1xx5/8`
`=-5/8`
D)
`3/7xx9/11+3/7xx2/11`
`=3/7xx(9/11+2/11)`
`=3/7xx11/11`
`=3/7xx1`
`=3/7`