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Ta có :

\(D=\frac{4^4.9^4+2.6^9}{2^{10}.3^8+6^8.20}\)

\(\Rightarrow D=\frac{\left(2^2\right)^4.\left(3^2\right)^4+2.6^9}{2^{10}.3^8+\left(2.3\right)^8.20}\)

\(\Rightarrow D=\frac{2^8.3^8+2.2^9.3^9}{2^{10}.3^8+2^8.3^8.2^2.5}\)

\(\Rightarrow D=\frac{\left(2^8.3^8\right).\left(1+2.2.3\right)}{\left(2^8.3^8\right).\left(2^2+2^2.5\right)}\)

\(\Rightarrow D=\frac{1+12}{4+4.5}=\frac{13}{24}\)

a) Ta có: \(\dfrac{-5}{7}\left(\dfrac{14}{5}-\dfrac{7}{10}\right):\left|-\dfrac{2}{3}\right|-\dfrac{3}{4}\left(\dfrac{8}{9}+\dfrac{16}{3}\right)+\dfrac{10}{3}\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\)

\(=\dfrac{-5}{7}\cdot\dfrac{3}{2}\cdot\dfrac{21}{10}-\dfrac{3}{4}\cdot\dfrac{56}{3}+\dfrac{10}{3}\cdot\dfrac{8}{15}\)

\(=\dfrac{-9}{4}-14+\dfrac{16}{9}\)

\(=\dfrac{-1621}{126}\)

b) Ta có: \(\dfrac{17}{-26}\cdot\left(\dfrac{1}{6}-\dfrac{5}{3}\right):\dfrac{17}{13}-\dfrac{20}{3}\left(\dfrac{2}{5}-\dfrac{1}{4}\right)+\dfrac{2}{3}\left(\dfrac{6}{5}-\dfrac{9}{2}\right)\)

\(=\dfrac{-17}{26}\cdot\dfrac{13}{17}\cdot\dfrac{-3}{2}-\dfrac{20}{3}\cdot\dfrac{3}{20}+\dfrac{2}{3}\cdot\dfrac{-33}{10}\)

\(=\dfrac{3}{4}-1-\dfrac{11}{5}\)

\(=-\dfrac{49}{20}\)

1: =72/90+65/90=137/90

2: =24/56-77/56=-53/56

3: =-7/10+4/5=1/10

4: =15/100-4/100=11/100

5: =4/6-5/6=-1/6

6: =10/40-15/40-76/40=-81/40

7: =-9/10+7/18

=-81/90+35/90=-46/90=-23/45

8: =27/90-55/90=-28/90=-14/45

9: =36/60-50/60-35/60=-49/60

10: =-4/9+5/6-3/8

=-32/72+60/72-27/72

=1/72

5 tháng 9 2018

https://iostudy.net/ref/133587

24 tháng 9 2018

Có : \(\dfrac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}=\dfrac{2^{10}.3^8-2.2^9.3^9}{2^{10}.3^8+2^8.3^8.2^2.5}=\dfrac{2^{10}.3^8-2^{10}.3^9}{2^{10}.3^8+2^{10}.3^8.5}=\dfrac{2^{10}.3^8\left(1-3\right)}{2^{10}.3^8\left(1+5\right)}=\dfrac{1-3}{1+5}=\dfrac{1}{3}\)

6 tháng 3 2023

câu a : 

\(\dfrac{-8}{24}+\dfrac{-4}{12}=\dfrac{-1}{3}+\dfrac{-1}{3}=\dfrac{-2}{3}\)

câu b : 

\(\dfrac{-20}{35}+\dfrac{16}{24}=\dfrac{-4}{7}+\dfrac{2}{3}=\dfrac{2}{21}\)

câu c : 

\(\dfrac{-3}{9}+\dfrac{-6}{15}=\dfrac{-1}{3}+\dfrac{-2}{5}=\dfrac{-11}{15}\)

câu d : 

\(\dfrac{3}{13}-\dfrac{4}{10}=\dfrac{3}{13}-\dfrac{2}{5}=\dfrac{-11}{65}\)

câu e : 

\(\dfrac{5}{17}-\dfrac{9}{15}=\dfrac{5}{17}-\dfrac{3}{5}=\dfrac{-26}{85}\)

câu g : 

\(\dfrac{9}{18}-\dfrac{6}{15}+\dfrac{3}{-9}=\dfrac{9}{18}-\dfrac{6}{15}+\dfrac{-3}{9}\\ =\dfrac{1}{2}-\dfrac{2}{5}+\dfrac{-1}{3}=\dfrac{-7}{30}\)

câu h : 

\(\dfrac{5}{4}-\dfrac{1}{2}+\dfrac{-7}{8}=\dfrac{10}{8}-\dfrac{4}{8}+\dfrac{-7}{8}=\dfrac{-1}{8}\)

15 tháng 11 2021

\(\dfrac{4^{^5}.9^{^4}-2.6^{^9}}{2^{^{10}}.3^{^8}+6^{^8}.20}\)=\(\dfrac{2^{^{10}}.3^{^8}-2.2^{^9}.3^{^9}}{2^{^{10}}.3^{^8}+2^{^8}.3^{^8}.2^{^2}.5}\)=\(\dfrac{2^{^{10}}.3^{^8}-2^{^{10}}.3^{^9}}{2^{^{10}}.3^{^8}+2^{^{10}}.3^{^8}.5}\)=\(\dfrac{2^{^{10}}.3^{^8}\left(1-3\right)}{2^{^{10}}.3^{^8}\left(1+5\right)}\)=\(\dfrac{1-3}{1+5}\)=\(\dfrac{1}{3}\)

26 tháng 11 2021

45.94−2.69210.38+68.2045.94−2.69210.38+68.20=210.38−2.29.39210.38+28.38.22.5210.38−2.29.39210.38+28.38.22.5=210.38−210.39210.38+210.38.5210.38−210.39210.38+210.38.5=210.38(1−3)210.38(1+5)210.38(1−3)210.38(1+5)=1−31+51−31+5=13

 

14 tháng 10 2021

-88829379