a) \(x-\dfrac{3}{5}=\dfrac{2}{7}\)

\(\Rightarrow x=\dfrac{2}{7}+\dfrac{3}{5}\)

\(\Rightarrow x=\dfrac{10}{35}+\dfrac{21}{35}\)

\(\Rightarrow x=\dfrac{31}{35}\)

b) \(x+\dfrac{20}{11\cdot13}+\dfrac{20}{13\cdot15}+...+\dfrac{20}{53\cdot55}=\dfrac{3}{11}\)

\(\Rightarrow x+10\left(\dfrac{2}{11\cdot13}+\dfrac{2}{13\cdot15}+...+\dfrac{2}{53\cdot55}\right)=\dfrac{3}{11}\)

\(\Rightarrow x+10\left(\dfrac{1}{11}-\dfrac{1}{13}+\dfrac{1}{13}-\dfrac{1}{15}+...+\dfrac{1}{53}-\dfrac{1}{55}\right)=\dfrac{3}{11}\)
\(\Rightarrow x+10\left(\dfrac{1}{11}-\dfrac{1}{55}\right)=\dfrac{3}{11}\)

\(\Rightarrow x+10\cdot\dfrac{4}{55}=\dfrac{3}{11}\)

\(\Rightarrow x+\dfrac{40}{55}=\dfrac{3}{11}\)

\(\Rightarrow x=\dfrac{3}{11}-\dfrac{40}{55}\)

\(\Rightarrow x=\dfrac{-25}{55}=\dfrac{-5}{11}\)

a) 

\(\dfrac{4}{5}-\left(\dfrac{-2}{3}\right)-\dfrac{1}{10}-\dfrac{2}{3}\\ =\dfrac{4}{5}+\dfrac{2}{3}-\dfrac{1}{10}-\dfrac{2}{3}\\ =\left(\dfrac{4}{5}-\dfrac{1}{10}\right)+\left(\dfrac{2}{3}-\dfrac{2}{3}\right)\\ =\dfrac{7}{10}+0\\ =\dfrac{7}{10}\)  

b) 

\(\dfrac{1}{3}-\dfrac{-1}{2}+\dfrac{1}{13}-\dfrac{5}{6}\\ =\left(\dfrac{1}{2}+\dfrac{1}{3}\right)+\dfrac{1}{13}-\dfrac{5}{6}\\ =\dfrac{5}{6}+\dfrac{1}{13}-\dfrac{5}{6}\\ =\dfrac{1}{13}\) 

c) 

\(\dfrac{-5}{12}-\left(\dfrac{-5}{6}-\dfrac{5}{12}\right)\\ =\dfrac{-5}{12}+\dfrac{5}{6}+\dfrac{5}{12}\\ =\left(-\dfrac{5}{12}+\dfrac{5}{12}\right)+\dfrac{5}{6}\\ =\dfrac{5}{6}\)

B. badly.

C. hardly

It's raining very hardly.

( Trời mưa nặng hạt.)

Ta có :

\(\dfrac{1300}{1500}=\dfrac{13}{15}=1-\dfrac{2}{15}\)

\(\dfrac{1333}{1555}=1-\dfrac{222}{1555}\)

Vì \(\dfrac{222}{1555}>\dfrac{2}{15}\)

\(\Rightarrow1-\dfrac{222}{1555}< 1-\dfrac{2}{15}\)

\(\dfrac{\Rightarrow1333}{1555}< \dfrac{1300}{1500}\)

hi

2. always read

3. ran

4. travelled

5. decided

2 always read

3 ran

4 travelled

5 decided 

\(\left(\dfrac{1}{2}-1\right).\left(\dfrac{1}{3}-1\right).\left(\dfrac{1}{4}-1\right)...\left(\dfrac{1}{2008}-1\right).\left(\dfrac{1}{2009}-1\right)\)

\(=-\dfrac{1}{2}.-\dfrac{2}{3}.-\dfrac{3}{4}...-\dfrac{2007}{2008}.-\dfrac{2008}{2009}\)

\(=-\left(\dfrac{1.2.3...2007.2008}{2.3.4...2008.2009}\right)\)

\(=-\dfrac{1}{2009}\)

getting - done

We are (get)getting  the work (do)done by a professional decorator and she is going to talk to me about all the changes

get st V3 by sb : nhờ cái gì được làm bởi ai

1 having

2 to fix

3 get our house painted

4 have the children taught to take off their shoes before they come into the house.

5 get Jake to help us with our project.

1. They are having/ getting sb pick them up at the airport

2. I really must get sb to fix/ fix the broken window

3. We need to paint our house soon PAINTED

We must ..have/get our house painted. soon

4. You should teach the children to take off thier shoes before they come into the house HAVE

You should have the children taught to take off thier shoes before they come into the house

5. Jake đin't want to help us with our project GET

We couldn't get jack to help us with our project

Tan.has lunch at twenty to twelve

Tan has lunch at twenty to twelve