\(\dfrac{7}{5}+\dfrac{4}{7}-\dfrac{9}{10}=\dfrac{49-20}{35}-\dfrac{9}{10}=\dfrac{19}{35}-\dfrac{9}{10}=\dfrac{190-315}{350}=\dfrac{-125}{350}\)

\(\dfrac{2}{1}+\dfrac{3}{4}\text{×}\dfrac{8}{5}=\dfrac{8+3}{4}\text{×}\dfrac{8}{5}=\dfrac{11\text{×}8}{4\text{×}5}=\dfrac{88}{20}\)

mấy câu kia áp dụng là dc!

\(\sqrt{51-7\sqrt{8}}=\sqrt{7^2-7.2\sqrt{2}+\left(\sqrt{2}\right)^2}=\sqrt{\left(7-\sqrt{2}\right)^2}=7-\sqrt{2}\)

(vì\(7=\sqrt{49}>\sqrt{2}\Rightarrow7-\sqrt{2}>0\))

pt sao có 1 vé vậy bạn

bài 7 nào vậy ghi đề đi

Câu 8 

a, \(\dfrac{4}{5}+\dfrac{3}{8}+\dfrac{1}{4}=\dfrac{16.4}{80}+\dfrac{30}{80}+\dfrac{20}{80}=\dfrac{64+50}{80}=\dfrac{114}{80}=\dfrac{57}{40}\)

b, \(\dfrac{5}{9}+\dfrac{2}{3}+\dfrac{1}{2}=\dfrac{10}{18}+\dfrac{12}{18}+\dfrac{9}{18}=\dfrac{22+9}{18}=\dfrac{31}{18}\)

Câu 8 

a, 59+23+12=1018+1218+918=22+918=3118

1. go / her / we / birthday / will / to / party

=> We will go to her birthday party

2. be / on / May / Lan / will / Sunday / 20th / thirteen.

=> Lan will be thirteen on Sunday 20th

3. will / her / call / six / after / I / again / o'clock

=> I will call her again after six o'clock

4. speak / can / to / I / Mai / please?

=> Can I speak to Mai please?

5. telephone / your / is / number / what?

=> What is your telephone number?

6. morning / will / free / you / be / tomorrow?

=> Will you be free tomorrow morning?

7. weekend / think / will / the / free / on / I / I / be

=> I think I will be free on the weekend.

8. of / invite / friends / some / will / she / her.

=> She will invite some of her friends.

bn lên google tra

mk tra dồi nhưng không có