e).

= \(\dfrac{9}{17}.\dfrac{3}{7}+\dfrac{9}{17}.\dfrac{4}{7}\)

= \(\dfrac{9}{17}.\left(\dfrac{3}{7}+\dfrac{4}{7}\right)=\dfrac{9}{17}.1=\dfrac{9}{17}\)

f) . 

cj nghĩ đề sai đk=)? mạnh dạn đoán=)

A = 6/19 . -7/11 + 6/19 . -4/11 + -13/19

A = 6/19 . [-7/11 + (-4/11)] + (-13/19)

A = 6/19 . -11/11 + (-13/19)

A = 6/19 . (-1) + (-13/19)

A = -6/19 + (-13/19)

A = -19/19

A = -1

Vậy A = -1

\(\dfrac{3}{4}\cdot\dfrac{7}{9}\cdot\dfrac{1}{9}\cdot\dfrac{7}{4}\)

\(=\dfrac{3\cdot7\cdot1\cdot7}{4\cdot9\cdot9\cdot4}=\dfrac{3\cdot7\cdot1\cdot7}{4\cdot3\cdot3\cdot9\cdot4}\)

\(=\dfrac{7\cdot1\cdot7}{4\cdot3\cdot9\cdot4}=\dfrac{49}{432}\)

\(\dfrac{6}{7}\cdot\dfrac{8}{13}-\dfrac{6}{9}\cdot\dfrac{9}{7}+\dfrac{5}{13}\cdot\dfrac{6}{7}\)

\(=\dfrac{6}{7}\cdot\dfrac{8}{13}-\dfrac{6}{7}+\dfrac{5}{13}\cdot\dfrac{6}{7}\)

\(=\dfrac{6}{7}\left(\dfrac{8}{13}-1+\dfrac{5}{13}\right)\)

\(=\dfrac{6}{7}\cdot0\)

\(=0\)

\(2\cdot11\cdot\dfrac{3}{4}\cdot\dfrac{9}{121}\)

\(=\dfrac{2\cdot11\cdot3\cdot9}{4\cdot121}=\dfrac{2\cdot11\cdot3\cdot9}{2\cdot2\cdot11\cdot11}\)

\(=\dfrac{3\cdot9}{2\cdot11}=\dfrac{27}{22}\)

bạn ơi, đề bài là gì vậy ạ?

a. \(\dfrac{3.7.1.7}{4.3.3.9.4}=\dfrac{49}{432}\)

b. \(\dfrac{6}{7}.\left(\dfrac{8}{13}+\dfrac{5}{13}-1\right)=\dfrac{6}{7}.0=0\)

\(\dfrac{2.11.3.9}{2.2.11.11}=\dfrac{27}{22}\)

a: =(2/7-2/7)(-4/7-5/9)=0

b:

Sửa đề: 9/13*(-12/17)+9/13*29/27

=9/13(-12/17+29/17)

=9/13*17/17=9/13

c: \(=\dfrac{1}{7}\left(4+\dfrac{6}{7}+\dfrac{8}{7}\right)=\dfrac{1}{7}\cdot6=\dfrac{6}{7}\)

d: =7/10(5/7+9/7+8/7+13/7)

=5*7/10=7/2

Đề bài yêu cầu gì?

B=5/7(-4/13+7/13-3/13)=5/7x0=0

\(\dfrac{1}{3}-\dfrac{3}{5}+\dfrac{5}{7}-\dfrac{7}{9}+\dfrac{9}{11}-\dfrac{11}{13}+\dfrac{13}{15}+\dfrac{11}{13}-\dfrac{9}{11}+\dfrac{7}{9}-\dfrac{5}{7}+\dfrac{3}{5}-\dfrac{1}{3}\)
\(=\left(\dfrac{1}{3}-\dfrac{1}{3}\right)-\left(\dfrac{3}{5}-\dfrac{3}{5}\right)+\left(\dfrac{5}{7}-\dfrac{5}{7}\right)-\left(\dfrac{7}{9}-\dfrac{7}{9}\right)+\left(\dfrac{9}{11}-\dfrac{9}{11}\right)-\left(\dfrac{11}{13}-\dfrac{11}{13}\right)+\dfrac{13}{15}\)
\(=\dfrac{13}{15}\)

31​−53​+75​−97​+119​−1311​+1513​+1311​−119​+97​−75​+53​−31​
=(13−13)−(35−35)+(57−57)−(79−79)+(911−911)−(1113−1113)+1315=(31​−31​)−(53​−53​)+(75​−75​)−(97​−97​)+(119​−119​)−(1311​−1311​)+1513​
=1315=1513​

 

\(\dfrac{6}{13}.\dfrac{5}{7}+\dfrac{6}{13}.\dfrac{2}{7}+\dfrac{7}{13}=\dfrac{6}{13}.\left(\dfrac{5}{7}+\dfrac{2}{7}\right)+\dfrac{7}{13}=\dfrac{6}{13}.1+\dfrac{7}{13}=\dfrac{6}{13}+\dfrac{7}{13}=\dfrac{13}{13}=1\)

#Monster

\(\dfrac{6}{13}\).(\(\dfrac{2}{7}+\dfrac{5}{7}\))+\(\dfrac{7}{13}\)

\(\dfrac{6}{13}\).1+\(\dfrac{7}{13}\)

\(\dfrac{6}{13}\)+\(\dfrac{7}{13}\)

1

mik làm ở bài dưới rồi nha.

\(A=\dfrac{6}{19}.\dfrac{-7}{11}+\dfrac{6}{19}.\dfrac{-4}{11}+\dfrac{-13}{19}\)

\(A=\dfrac{6}{19}.\left(\dfrac{-7}{11}+\dfrac{-4}{11}\right)+\dfrac{-13}{19}\)

\(A=\dfrac{6}{19}.-1+\dfrac{-13}{19}=\dfrac{-6}{19}+\dfrac{-13}{19}=\dfrac{-19}{19}=-1\)

57.−413+57.73−513.37" id="MathJax-Element-2-Frame" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline-table; font-size:18px; font-style:normal; font-weight:normal; letter-spacing:normal; line-height:normal; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; padding:0px; position:relative; text-align:left; text-indent:0px; text-transform:none; white-space:nowrap; word-spacing:normal; word-wrap:normal" tabindex="0">B=57.−413+57.73−513.37

57.−413+57.73−513.37" id="MathJax-Element-2-Frame" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline-table; font-size:18px; font-style:normal; font-weight:normal; letter-spacing:normal; line-height:normal; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; padding:0px; position:relative; text-align:left; text-indent:0px; text-transform:none; white-space:nowrap; word-spacing:normal; word-wrap:normal" tabindex="0">B=57.−413+57.73− \(\dfrac{5}{7}.\dfrac{3}{13}\)3

7

\(B=\dfrac{5}{7}.\left(\dfrac{-4}{13}+\dfrac{7}{3}-\dfrac{3}{13}\right)\)

\(B=\dfrac{5}{7}.\dfrac{70}{39}=\dfrac{350}{273}\)

Câu B ko rõ lắm

\(B=\dfrac{5}{7}.\dfrac{-4}{13}+\dfrac{5}{7}.\dfrac{7}{3}-\dfrac{5}{13}.\dfrac{3}{7}\)

\(B=\dfrac{5}{7}.\dfrac{-4}{13}+\dfrac{5}{7}.\dfrac{7}{3}-\dfrac{5}{7}.\dfrac{3}{13}\)

Rồi tiếp 2 câu rõ

-5/7.(4/13-15/3-2/13)

=45/13

\(=\dfrac{-5}{7}\left(\dfrac{4}{13}-\dfrac{15}{3}-\dfrac{2}{13}\right)\)

\(=\dfrac{-5}{7}\times\dfrac{-63}{13}=\dfrac{45}{13}\)

45/13