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a: \(=\dfrac{5^{42}\cdot7^{30}}{5^{40}\cdot7^{30}\cdot10}=\dfrac{5^2}{10}=\dfrac{25}{10}=\dfrac{5}{2}\)

b: \(=\dfrac{3^{18}\cdot5^{10}}{5^{10}\cdot3^{10}\cdot3^9}=\dfrac{1}{3}\)

5 tháng 10 2016

\(A=\frac{81^4.3^{10}.27^5:3^{12}}{3^{18}:9^3.243^2}=\frac{3^{16}.3^{10}.3^{15}:3^{12}}{3^{18}:3^6.3^{10}}=\frac{3^{29}}{3^{22}}=3^7\)

\(B=\frac{2.55^2-9.55^{21}}{25^{10}}:\frac{5\left(3.7^{15}-19.7^{14}\right)}{7^{16}+3.7^{15}}=\frac{2.55^2-9.55^2.55^{19}}{25^{10}}:\frac{5\left(21.7^{14}-19.7^{14}\right)}{7.7^{15}+3.7^{15}}=\frac{55^2\left(55^{19}.9-2\right)}{25^{10}}:\frac{5.7^{14}.2}{7^{15}.10}=\frac{55^2\left(55^{19}.9-2\right)}{25^{10}}.\frac{7^{15}.10}{5.7^{14}.2}\)Chịu ==

4 tháng 10 2021

yutyugubhujyikiu

7 tháng 12 2023

(-12) + (-18)

= -30

------------------

(-90) + 27 + (-10) + 73

= [(-90) + (-10) + (27 + 73)

= -100 + 100

= 0

---------------------------------

25 . (-5) . (-4)

= 25 . (-4) . (-5)

= -100 . (-5)

= 100 . 5

= 500

----------------------------------------

(-15) . 40 : 6

= [(-15) . 40] : 6 

= (-600) : 6

= -100

-----------------------------------

(-27) . 58 + (-27) . 42

= (-27) . (58 + 42)

= (-27) . 100

= -2700

 

7 tháng 3 2018

b)  \(\frac{4}{10}+\frac{-2}{9}+\frac{-3}{-5}+\frac{21}{-27}+\frac{-10}{20}\)

\(=\frac{2}{5}-\frac{2}{9}+\frac{3}{5}-\frac{7}{9}-\frac{1}{2}\)

\(=\left(\frac{2}{5}+\frac{3}{5}\right)-\left(\frac{2}{9}+\frac{7}{9}\right)-\frac{1}{2}\)

\(=1-1-\frac{1}{2}=-\frac{1}{2}\)

7 tháng 3 2018

a)  \(-\frac{5}{2}+\frac{1}{7}+\frac{6}{7}+\frac{1}{2}+\frac{3}{4}\)

\(=\left(\frac{-5}{2}+\frac{1}{2}\right)+\left(\frac{1}{7}+\frac{6}{7}\right)+\frac{3}{4}\)

\(=-2+1+\frac{3}{4}\)

\(=-1+\frac{3}{4}\)

\(=-\frac{1}{4}\)

\(x\left(x-2\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x-2=0\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x=2\end{cases}}\)

16 tháng 7 2016

a)\(1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}\)

\(=\left(1\frac{4}{23}-\frac{4}{23}\right)+\left(\frac{5}{21}+\frac{16}{21}\right)+0,5\)

\(=1+1+0,5\)

\(=2,5\)

b)\(\frac{3}{7}.19\frac{1}{3}-\frac{3}{7}.33\frac{1}{3}\)

\(=\frac{3}{7}.\left(19\frac{1}{3}-33\frac{1}{3}\right)\)

\(=\frac{3}{7}.\left(-14\right)\)

\(=-6\)

c)\(9.\left(-\frac{1}{3}\right)^3+\frac{1}{3}\)

\(=9.\left(-\frac{1}{3}\right)^3+9.\frac{1}{27}\)

\(=9.\left[\left(-\frac{1}{3}\right)^3+\frac{1}{27}\right]\)

\(=9.0=0\)

d)\(15\frac{1}{4}:\left(-\frac{5}{7}\right)-25\frac{1}{4}:\left(-\frac{5}{7}\right)\)

\(=\left(15\frac{1}{4}-25\frac{1}{4}\right):\left(-\frac{5}{7}\right)\)

\(=\left(-10\right):\left(-\frac{5}{7}\right)\)

\(=14\)