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đáp án:

\(x=\frac{47}{111}\)

\(\frac{5}{6}\cdot x+\frac{2}{3}\cdot\left(\frac{3}{5}\cdot x-\frac{6}{5}\right)=\frac{2}{9}-\frac{1}{2}\)

\(\Rightarrow\frac{5}{6}\cdot x+\frac{2}{3}\cdot\frac{3}{5}\cdot x-\frac{2}{3}\cdot\frac{6}{5}=-\frac{5}{18}\)

\(\Rightarrow\frac{5}{6}\cdot x+\frac{2}{5}\cdot x-\frac{4}{5}=-\frac{5}{18}\)

\(\Rightarrow x\cdot\left(\frac{5}{6}+\frac{2}{5}\right)=-\frac{5}{18}+\frac{4}{5}\)

\(\Rightarrow x\cdot\frac{37}{30}=\frac{47}{90}\)

\(\Rightarrow x=\frac{47}{90}\div\frac{37}{30}\)

\(\Rightarrow x=\frac{47}{111}\)

Vậy \(x=\frac{47}{111}\)

1)1/6 - - 5/6 = 1/6 + 5/6 = 1

2)6/13 - -14/39 = 6/13 + 14/39= 32/39

3)4/5 - 4/-18 = 4/5 + 4/18= 46/45

4)7/21 - 9/-36 = 7/21 + 9/36 = 7/12

5)-12/18 - -21/35  = -12/18 + 21/35 = -1/15

6)-3/21 - 6/42 = -2/7

7)-18/24 - 15/21 = -41/28

8)1/6 - 2/5 =-7/30

\(P=4^{25}\cdot\left(\dfrac{1}{2}-\dfrac{1}{3}\right)\cdot\left(\dfrac{1}{2}-\dfrac{1}{5}\right)\cdot\left(\dfrac{1}{2}-\dfrac{1}{7}\right)\cdot...\cdot\left(\dfrac{1}{2}-\dfrac{1}{101}\right)\)

\(P=4^{25}\cdot\left(\dfrac{1}{2}\cdot\left(\dfrac{1}{3}+\dfrac{1}{5}+\dfrac{1}{7}-...+\dfrac{1}{101}\right)\right)\)

\(P=4^{25}\cdot\left(\dfrac{1}{2}\cdot\left(\dfrac{1}{101}-\dfrac{1}{3}\right)\div2+1\right)\)

\(P=4^{25}\cdot\left(\dfrac{1}{2}\cdot\dfrac{1}{50}\right)\)

\(P=4^{25}\cdot\dfrac{1}{100}\)

a: Xét tứ giác ABNM có 

AM//BN

AM=BN

Do đó: ABNM là hình bình hành

mà \(\widehat{MAB}=90^0\)

nên ABNM là hình chữ nhật

ngắn thui chứ