84. My mother often flies to HCM.

85. I don't play as well as Hoa

90. Why can't I visit you tomorrow?

92. How wide is the Great Wall?

83. How long does it take you to ride to school?

Học tốt

90 .Why I can't visit me tomorrow ?

92 . How wide is the Great Wall ? 

93 . How long it take you to ride to school .

a/b là phân số nha

\(\left(\frac{7}{20}+\frac{11}{15}-\frac{15}{12}\right):\left(\frac{11}{20}-\frac{26}{45}\right)\)

\(=\left(\frac{21}{60}+\frac{44}{60}-\frac{75}{60}\right):\left(\frac{99}{180}-\frac{104}{180}\right)\)

\(=-\frac{1}{6}:\frac{-1}{36}\)

\(=\frac{-36}{-6}\)

\(=6\)

not => don't

Học tốt

Answer :

not -> x

If we plant many trees, the air will be fresh.

Đề đúng o bạn

có dấu .. ko vậy

1. Hình như sai đề bài thì phải, cái 1,8 trong sách là 1,2 mà. Mà tính 1,8 nó cứ ra phân số ý.

2.Giải

Chiều rộng khu vườn là:

5/9 x 36 = 20(m)

S khu vườn là:

36 x 20 = 720 = 7200000(cm²)

S khu vườn trên bản đồ tỉ lệ 1:1000 là:

7200000 : 1000= 7200(cm²)

\(a,\left[\frac{4}{5}+\frac{2}{3}\right]:\frac{1}{5}-1,4\cdot\left[\frac{-5}{7}\right]^2\)

\(=\left[\frac{4\cdot3}{15}+\frac{2\cdot5}{15}\right]:\frac{1}{5}-1,4\cdot\frac{-5}{7}\cdot\frac{-5}{7}\)

\(=\left[\frac{12}{15}+\frac{10}{15}\right]:\frac{1}{5}-\frac{14}{10}\cdot\frac{25}{49}\)

\(=\frac{22}{15}:\frac{1}{5}-\frac{7}{5}\cdot\frac{25}{49}\)

\(=\frac{22}{15}\cdot\frac{5}{1}-\frac{7}{5}\cdot\frac{25}{49}\)

\(=\frac{22\cdot5}{15\cdot1}-\frac{7\cdot25}{5\cdot49}=\frac{22\cdot1}{3\cdot1}-\frac{1\cdot5}{1\cdot7}=\frac{22}{3}-\frac{5}{7}\)

= ...

Tự tính

Bài 2 : \(a,3-\left|\frac{1}{2}x-\frac{1}{3}\right|=\frac{1}{2}\)

\(\Rightarrow\left|\frac{1}{2}x-\frac{1}{3}\right|=\frac{1}{2}+3\)

\(\Rightarrow\left|\frac{1}{2}x-\frac{1}{3}\right|=\frac{7}{2}\)

\(\Rightarrow\hept{\begin{cases}\frac{1}{2}x-\frac{1}{3}=\frac{7}{2}\\\frac{1}{2}x-\frac{1}{3}=-\frac{7}{2}\end{cases}}\Rightarrow\hept{\begin{cases}x=\frac{23}{3}\\x=\frac{-19}{3}\end{cases}}\)

Vậy \(x\in\left\{\frac{23}{3};\frac{-19}{3}\right\}\)

b, \(0,6-160\%< x\le3\frac{2}{3}:\frac{22}{18}\)

\(\Rightarrow0,6-\frac{160}{100}< x\le\frac{11}{3}:\frac{22}{18}\)

\(\Rightarrow0,6-\frac{8}{5}< x\le\frac{11}{3}\cdot\frac{18}{22}\)

\(\Rightarrow0,6-1,6< x\le3\)

\(\Rightarrow-1< x\le3\)

\(\Rightarrow x\in\left\{0;1;2;3\right\}\)