Thực hiện phép tính hợp lí;
a) \(\left(\dfrac{9}{25}-2,18\right):\left(3\dfrac{4}{5}+0,2\right)\)
b) \(\dfrac{3}{8}.19\dfrac{1}{3}-\dfrac{3}{8}.33\dfrac{1}{3}\)
c) \(1\dfrac{4}{23}+\dfrac{5}{21}-\dfrac{4}{23}+0,5+\dfrac{16}{21}\)
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5: =5/7(5/11+2/11-14/11)
=5/7*(-7/11)
=-5/11
6: =-5/4(2/11+9/11)+1+3/4
=7/4-5/4=1/2
7: =-5/7(3/13+10/13)+1+5/7
=1
8: =7/4(29/5-9/5)+3+2/13
=3+2/13+7/4*4
=10+2/13
=132/13
c: \(=\left(\dfrac{3}{5}+\dfrac{83}{200}-\dfrac{3}{200}\right)\cdot\dfrac{8}{3}\cdot\dfrac{1}{4}=\dfrac{8}{3}\cdot\dfrac{1}{4}=\dfrac{2}{3}\)
g: \(=\dfrac{1}{2}\cdot\dfrac{4}{3}\cdot\dfrac{3}{4}\cdot\dfrac{5}{2}+\dfrac{3}{5}=\dfrac{5}{4}+\dfrac{3}{5}=\dfrac{25+12}{20}=\dfrac{37}{20}\)
e: \(=\dfrac{21-6}{8}\cdot\dfrac{16}{3}=\dfrac{15}{3}\cdot2=10\)
f: \(=\dfrac{-3\cdot3+7\cdot4}{12}:\dfrac{2\cdot2-5\cdot9}{18}\)
\(=\dfrac{19}{12}\cdot\dfrac{18}{-41}=\dfrac{-57}{82}\)
g: \(=\dfrac{9-8}{10}\cdot\dfrac{5}{2}+1=\dfrac{1}{10}\cdot\dfrac{5}{2}+1=\dfrac{1}{4}+1=\dfrac{5}{4}\)
o: \(=\dfrac{3}{4}\cdot\left[\dfrac{1}{5}-\dfrac{4}{7}-\dfrac{3}{5}\cdot\dfrac{-5}{7}\right]=\dfrac{3}{4}\cdot\left(\dfrac{1}{5}-\dfrac{4}{7}+\dfrac{3}{7}\right)\)
\(=\dfrac{3}{4}\cdot\left(\dfrac{1}{5}-\dfrac{1}{7}\right)=\dfrac{3}{4}\cdot\dfrac{2}{35}=\dfrac{3}{70}\)
p: \(=\left[\left(\dfrac{1}{9}\cdot\dfrac{27}{8}\right)\cdot3\right]\cdot\dfrac{-128}{81}=\dfrac{9}{8}\cdot\dfrac{-128}{81}=\dfrac{-16}{9}\)
a)Ta có:\(\left(\dfrac{9}{25}-2,18\right):\left(3\dfrac{4}{5}+0,2\right)=-1,82:4=-\dfrac{91}{200}=-0,455\)
b)Ta có:\(\dfrac{3}{8}.19\dfrac{1}{3}-\dfrac{3}{8}.33\dfrac{1}{3}=\dfrac{3}{8}\left(19\dfrac{1}{3}-33\dfrac{1}{3}\right)=\dfrac{3}{8}.\left(-14\right)=-\dfrac{21}{4}=-5,25\)
c)Ta có:\(1\dfrac{4}{23}+\dfrac{5}{21}-\dfrac{4}{23}+0,5+\dfrac{16}{21}=(1\dfrac{4}{23}-\dfrac{4}{23})+\left(\dfrac{5}{21}+\dfrac{16}{21}\right)+0,5=1+1+0,5=2,5\)Chúc bạn học tốt!!