\(=\frac{\left(2^{20}-1^{20}+3^{20}\right)\cdot2^{20}}{\left(2^{20}-1^{20}+3^{20}\right)\cdot3^{20}}\left(\text{Mình làm hơi tắt, xin bạn thông cảm}\right)\)

\(=\frac{2^{20}}{3^{20}}=\left(\frac{2}{3}\right)^{20}\)

Uk mk nhận nha

a) \(=\left(13\dfrac{2}{7}+2\dfrac{5}{7}\right):\left(-\dfrac{8}{9}\right)\)

\(=16:\dfrac{-8}{9}=\dfrac{-8\cdot\left(-2\right)\cdot9}{-8}=-18\)

b) 

\(=\left(\dfrac{-6}{11}\cdot\dfrac{11}{-6}\right)\cdot\dfrac{7\cdot10\cdot\left(-2\right)}{10}\)

\(=-14\)

c) \(=\dfrac{-1}{2}\cdot\dfrac{4}{3}\cdot\dfrac{-7}{2}\)

\(=\dfrac{-1\cdot2\cdot2\cdot\left(-7\right)}{2\cdot3\cdot2}=\dfrac{7}{3}\)

`4 / 15 . 1 / 3 . 15 / 20`

`= [ 4 . 1 . 15 ] / [ 15 . 3 . 20 ]`

`= [ 4 . 1 . 15 ] / [ 15 . 3 . 4 . 5 ]`

`= 1 / [ 3 . 5 ]`

`= 1 / 15`

\(=\left(\dfrac{4}{15}.\dfrac{15}{20}\right).\dfrac{1}{3}=\dfrac{60}{300}.\dfrac{1}{3}=\dfrac{60}{900}=\dfrac{1}{15}\)

\(=\dfrac{4.1.15}{15.3.5.4}=\dfrac{1}{3.5}=\dfrac{1}{15}\)

\(a.\left[-\dfrac{6}{11}.\dfrac{11}{-6}\right].\dfrac{7}{10}.\left(-20\right)=1.7.\left(-2\right)=-14\)

\(b.\dfrac{-1}{2}:\dfrac{3}{4}.\dfrac{-7}{2}=\dfrac{7}{4}:\dfrac{3}{4}=\dfrac{7}{3}\)

\(c.\dfrac{93}{7}:-\dfrac{8}{9}+\dfrac{19}{7}:\dfrac{-8}{9}=\left(\dfrac{93}{7}+\dfrac{19}{7}\right):-\dfrac{8}{9}=\dfrac{-9}{8}.\dfrac{112}{7}=-18\)

Lời giải:
\(\frac{20^4.15^5}{12^5.25^4}=\frac{(2^2.5)^4.(3.5)^5}{(2^2.3)^5.(5^2)^4}=\frac{2^8.5^4.3^5.5^5}{2^{10}.3^5.5^8}\)

\(=\frac{2^8.5^9.3^5}{2^{10}.3^5.5^8}=\frac{2^8.5^8.5.3^5}{2^8.2^2.3^5.5^8}=\frac{5}{2^2}=\frac{5}{4}\)

\(=\dfrac{102}{5}\cdot\dfrac{6}{5}-\dfrac{107}{3}\cdot\dfrac{6}{5}-\dfrac{3}{4}\)

\(=\dfrac{6}{5}\cdot\dfrac{-229}{15}-\dfrac{3}{4}\)

\(=\dfrac{-458}{25}-\dfrac{3}{4}=-\dfrac{1907}{100}\)

= 102/5 x 6/5 - 107/3 x 6/5 - 3/4

= 6/5 x ( 102/5 - 107/3 ) - 3/4

= 6/5 x -229/15 - 3/4

= -458/25 - 3/4

= -1907/100

\(a,\dfrac{3}{5}+\dfrac{1}{5}.\dfrac{-17}{9}=\dfrac{3}{5}-\dfrac{17}{45}=\dfrac{27}{45}-\dfrac{17}{45}=\dfrac{10}{45}=\dfrac{2}{9}\\ b,\left(-\dfrac{4}{15}-\dfrac{18}{19}\right)-\left(\dfrac{20}{19}+\dfrac{11}{15}\right)=-\dfrac{4}{15}-\dfrac{18}{19}-\dfrac{20}{19}-\dfrac{11}{15}=\left(-\dfrac{4}{15}-\dfrac{11}{15}\right)-\left(\dfrac{18}{19}+\dfrac{20}{19}\right)=-1-2=-3\)

\(a,=\dfrac{3}{5}+\left(-\dfrac{17}{45}\right)=\dfrac{2}{9}\)

\(b,=-\dfrac{4}{15}-\dfrac{18}{19}-\dfrac{20}{19}-\dfrac{11}{15}=-3\)

a. 3/5+1/5.-17/9

=3/5+-17/45

=27/45+-17/45

=2/9

b. (-4/15-18/19)-(20/19+11/15)

=-4/15-18/19-20/19-11/15

=(-4/15-11/15)-(18/19-20/19)

=(-1)-(-2/19)

=(-19/19)-(-2/19)

=-17/19  

a.2/9
b.-3

a.2/9 b.(-3)

a.2/9
b.-3

\(\dfrac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}:\sqrt{\dfrac{25}{9}}=\dfrac{2^{10}.3^8-2.2^9.3^9}{2^{10}.3^8+2^8.3^8.2^2.5}:\dfrac{5}{3}\)

\(=\dfrac{2^{10}.3^8-2^{10}.3^9}{2^{10}.3^8+2^{10}.3^8.5}.\dfrac{5}{3}=\dfrac{2^{10}.3^8\left(1-3\right)}{2^{10}.3^8\left(1-5\right)}.\dfrac{5}{3}=\dfrac{1-3}{1-5}.\dfrac{5}{3}=\dfrac{1}{2}.\dfrac{5}{3}=\dfrac{5}{6}\)

\(\dfrac{4^5\cdot9^4-2\cdot6^9}{2^{10}\cdot3^8+6^8\cdot20}\div\sqrt{\dfrac{25}{9}}\)

\(=\dfrac{2^{10}\cdot3^8-2\cdot2^9\cdot3^9}{2^{10}\cdot3^8+2^8\cdot3^8\cdot2^2\cdot5}\div\dfrac{5}{4}\)

=\(\dfrac{2^{10}\cdot3^8\left(1-2\cdot3\right)}{2^{10}\cdot3^8\left(1+5\right)}\div\dfrac{5}{4}\)

=\(\dfrac{1-6}{1+5}\cdot\dfrac{4}{5}\)

=\(-\dfrac{5}{6}\cdot\dfrac{4}{5}\)

=\(-\dfrac{2}{3}\)