\(\frac{\left(\frac{36}{41}:\frac{9}{41}\right)}{\left(\frac{14}{21}:\frac{7}{21}\right)}\times\frac{2}{5}\)

\(=\frac{\left(\frac{36}{41}\times\frac{41}{9}\right)}{\left(\frac{14}{21}\times\frac{21}{7}\right)}\times\frac{2}{5}\)

\(=\frac{4}{2}\times\frac{2}{5}\)

\(=\frac{4}{5}\)

~ Ủng hộ nhé 

\(\frac{\text{36/41 : 9/41 }}{\text{14/21: 7/21}}\)= \(\frac{4}{2}\)= 2 => 2 x \(\frac{2}{5}\)= \(\frac{4}{5}\)

\(\frac{\left(\frac{36}{41}:\frac{9}{41}\right)}{\left(\frac{14}{21}:\frac{7}{21}\right)}\times\frac{2}{5}\)

\(=\frac{4}{\left(\frac{2}{3}:\frac{1}{3}\right)}\times\frac{2}{5}\)

\(=\frac{4}{2}\times\frac{2}{5}\)

\(=\frac{4}{5}\)

A.-9/2

b.-5/7

C.5/287

D.302/105

nêu cách tính nha bạn 

kho the

Tính giá trị biểu thức ạ

a)[(\(\frac{36}{41}\): \(\frac{9}{41}\)) : (\(\frac{14}{21}\):\(\frac{7}{21}\)) x \(\frac{2}{5}\)]

=[ 4 : 2 x \(\frac{2}{5}\)]

=\(\frac{4}{5}\)

b) (\(\frac{1}{2}\)- \(\frac{1}{4}\)+\(\frac{1}{5}\)) : (\(\frac{1}{2}\)+ \(\frac{1}{4}\)'- \(\frac{1}{5}\))

=\(\frac{9}{20}\): \(\frac{11}{20}\)

=\(\frac{9}{11}\)

( Mình tính luôn cho nó nhanh phần cuối cùng nhá)

=\(\frac{4}{5}\): \(\frac{3}{5}\)

=\(\frac{4}{3}\)

A = [(36/41 : 9/41)  : ( 14/21 : 7 /21) . 2/5]

A = [( 36/41 . 41/9 ) : ( 14/21 . 21/7 ) .2/5]

A =     4                 :            2          . 2/5

A =                      2                         . 2/5

A =         4/5

còn lại thì bạn tự làm nhé 

nhớ

\(\frac{5}{11.16}+\frac{5}{16.21}+..+\frac{5}{36.41}\)

\(=\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+..+\frac{1}{36}-\frac{1}{41}\)

\(=\frac{1}{11}-\frac{1}{41}\)

= bn tự timnhs nha......................................

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

\(\frac{5}{11.16}+\frac{5}{16.21}+...+\frac{5}{36.41}\)

\(=\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+...+\frac{1}{36}-\frac{1}{41}\)

\(=\frac{1}{11}-\frac{1}{41}\)

\(=\frac{30}{451}\)

_Chúc bạn học tốt_

\(A=\frac{5}{11\times16}+\frac{5}{16\times21}+....+\frac{5}{36\times41}.\)

\(A=\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+...+\frac{1}{36}-\frac{1}{41}\)

\(A=\frac{1}{11}-\frac{4}{41}=\frac{30}{451}\)

\(-\dfrac{5}{7}\left(\dfrac{-19}{41}+-\dfrac{21}{41}+1\right)=-\dfrac{5}{7}.\dfrac{1}{41}=-\dfrac{5}{287}\)

\(=\dfrac{-5}{7}\left(\dfrac{19}{41}+\dfrac{21}{41}-1\right)=\dfrac{-5}{7}\cdot\dfrac{-1}{41}=\dfrac{5}{287}\)

= 5/287

= -103/273

= 0

= -5/7

5.\(-\dfrac{3}{7}+\dfrac{5}{13}+\dfrac{-4}{12}=-\dfrac{103}{273}\)

b.\(-\dfrac{5}{21}+\dfrac{-2}{21}+\dfrac{8}{24}=\dfrac{-5-2}{21}+\dfrac{8}{24}=-\dfrac{7}{21}+\dfrac{8}{24}=-\dfrac{1}{3}+\dfrac{8}{24}=0\)

c.\(\dfrac{5}{13}+\dfrac{-5}{7}+\dfrac{-20}{41}+\dfrac{8}{13}+\dfrac{-21}{41}=\left(\dfrac{5}{13}+\dfrac{8}{13}\right)+\left(\dfrac{-20}{41}+\dfrac{-21}{41}\right)+-\dfrac{5}{7}=1-1-\dfrac{5}{7}=-\dfrac{5}{7}\)

1: =5/13+8/13-20/41-21/41-5/17

=1-1-5/17=-5/17

2: =1/5+4/5-2/9-7/9+16/17

=16/17+1-1=16/17

3: =1/3-1/5+1/5-1/7+...+1/99-1/101

=1/3-1/101

=98/303

-0.71428571428

Trả lời :

5/13 + - 5/7 + - 20/41 + 8/13 - 21/41 = -0.71428571428

~ Học tốt ~

Bài làm :