\(\frac{\frac{3}{4}-\frac{3}{5}+\frac{3}{7}+\frac{3}{11}}{\frac{13}{4}-\frac{13}{5}+\frac{13}{7}+\frac{13}{11}}=\frac{3\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{11}\right)}{13\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{11}\right)}=\frac{3}{13}\)

Mik làm từ trên xuống đưới nha

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HT

dap an la 
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=>125(3x+2):13=1000:13

=>125(3x+2)=1000

=>3x+2=8

=>x=2

A = (26/15 - 11/15) + (-7/13 + -6/13)

= 15/15 + -13/13

= 1 + (-1)

=0

a/\(\dfrac{26}{15}+-\dfrac{7}{13}+-\dfrac{6}{13}-\dfrac{11}{15}\)
\(=\left(\dfrac{26}{15}-\dfrac{11}{15}\right)-\left(\dfrac{7}{13}+\dfrac{6}{13}\right)\)
\(=1-1\)
\(=0\)
b/Sửa đề:
\(-\dfrac{3}{4}\cdot\dfrac{4}{13}+-\dfrac{3}{4}\cdot\dfrac{9}{13}+\dfrac{3}{4}\)
\(=-\dfrac{3}{4}\cdot\left(\dfrac{4}{13}+\dfrac{9}{13}\right)+\dfrac{3}{4}\)
\(=-\dfrac{3}{4}\cdot1+\dfrac{3}{4}\)
\(=-\dfrac{3}{4}+\dfrac{3}{4}\)
\(=0\)

Chọn D

D

Phương pháp giải:

Trừ nhẩm các số rồi điền kết quả thích hợp vào chỗ trống.

Lời giải chi tiết:

13 − 9 = 4            13 − 8 = 5

13 − 5 = 8            13 − 6 = 7

13 − 4 = 9            13 − 7 = 6

13 − 3 − 2 = 8      13 − 5 = 8

`3/13 . 15/11 + 3/13 . 7/11 -3/13`

`= 3/13 . 15/11 + 3/13 . 7/11 -3/13 .1`

`= 3/13 . (15/11 + 7/11 -11/11)`

`= 3/13 . 11/11`

`= 3/13 . 1`

`=3/13`

M là Minh:)))

\(\dfrac{-4}{3}-\dfrac{5}{7}+\dfrac{4}{3}=\left(\dfrac{4}{3}+\dfrac{-4}{3}\right)-\dfrac{5}{7}=0-\dfrac{5}{7}=-\dfrac{5}{7}\)

\(\dfrac{3}{13}\cdot\dfrac{6}{11}+\dfrac{3}{13}\cdot\dfrac{9}{11}-\dfrac{3}{13}\cdot\dfrac{4}{11}=\dfrac{3}{13}\cdot\left(\dfrac{6}{11}+\dfrac{9}{11}-\dfrac{4}{11}\right)=\dfrac{3}{13}\cdot1=\dfrac{3}{13}\)

cảm ơn bạn.