xin lỗi mik mới lớp 6

-4;-3;-2;-1 nha bạn.

\(4\frac{5}{9}:2\frac{5}{18}-7< x< \left(3\frac{1}{5}:3,2+4,5\cdot1\frac{31}{45}\right):\left(-21\frac{1}{2}\right)\)

\(\Leftrightarrow\frac{41}{9}:\frac{41}{18}-7< x< \left(\frac{16}{5}:\frac{16}{5}+\frac{9}{2}\cdot\frac{76}{45}\right):\left(-\frac{43}{2}\right)\)

\(\Leftrightarrow\frac{41}{9}\cdot\frac{18}{41}-7< x< \frac{43}{5}:\left(-\frac{43}{2}\right)\)

\(\Leftrightarrow2-7< x< -\frac{2}{5}\)

\(\Leftrightarrow-5< x< -0,4\)

\(\Leftrightarrow x\in\left\{-4;-3;-2;-1\right\}\)

\(H=\frac{1}{100}-\frac{1}{100\cdot99}-\frac{1}{99\cdot98}-...-\frac{1}{2\cdot1}\)

\(U=\frac{1}{100}-\left(\frac{1}{100\cdot99}+\frac{1}{99\cdot98}+...+\frac{1}{2\cdot1}\right)\)

\(U=\frac{1}{100}-\left(\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+...+\frac{1}{99\cdot100}\right)\)

\(H=\frac{1}{100}-\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{99}-\frac{1}{100}\right)\)

\(HU=\frac{1}{100}-\left(1-\frac{1}{100}\right)\)

\(UH=\frac{1}{100}-1+\frac{1}{100}\)

\(HU=\frac{2}{100}-1=-\frac{49}{50}\)

Chậc =)))

chac j` vay` cu'ng

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Ta có: 1/2 - (1/3 + 1/4) = 1/2 - 7/12 = -1/12 ;

           1/48 - (1/16 - 1/6) = 1/48 + 5/48 = 1/8

Vì \(-\frac{1}{12}< x< \frac{1}{8}\) nên x = 0

Ta có :

\(4\frac{5}{9}:2\frac{5}{18}-7=2-7=-5\)

\(\left(3\frac{1}{5}:3,2+4,5.1\frac{31}{45}\right):\left(-21\frac{2}{3}\right)=\left(1+\frac{38}{5}\right):\left(-21\frac{2}{3}\right)=\frac{43}{5}:\frac{-65}{3}=-\frac{129}{325}\)

Vì \(-5< x< -\frac{129}{325}\) nên \(x\in\left\{-4;-3;-2;-1\right\}\)