1. My sister ( get ) ......got...........  married last month
2. Daisy ( come ) ...came........... to her grandparents' house 3 days ago.
3. My computer ( be ) .....was.......... broken yesterday.
4. He ( buy ) .....bought............. me a big teddy bear on my birthday last week.
5. My friend ( give ) .....gave......... me a bar of chocolate when I ( be ) ....was............. at school yesterday.
6. My children ( not do ) ....didn't do............... their homework last night.
7. Did you ( live ) ....live................ here five years ago ?
8. They ( watch ) ....watched............... TV last at night yesterday.
9. Did your friend ( be ) .......was................... at your house last weekend ?
10. They ( not be ) .....wasn't.................... excited about the film last night.

1.got          5.give/was          9.was your friend

2.came      6.didn't do          10.weren't

3.was         7.Did you live

4.bought    8.watched

Có ai bít bài này ko ạ !

(\(\frac{-1}{2}\)) -(\(\frac{-3}{5}\))+(\(\frac{-1}{9}\))+\(\frac{1}{127}\)-\(\frac{7}{18}\)+\(\frac{4}{35}\)-(\(\frac{-2}{7}\))=\(\frac{448}{1143}\)

Ta có : \(\frac{1}{3.7}+\frac{1}{7.11}+...+\frac{1}{x.\left(x+4\right)}=\frac{5}{63}\)

=> \(\frac{1}{4}.\left(\frac{4}{3.7}+\frac{4}{7.11}+...+\frac{4}{x\left(x+4\right)}\right)=\frac{5}{63}\)

=> \(\frac{1}{3}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+...+\frac{1}{x}-\frac{1}{x+1}=\frac{20}{63}\)

=> \(\frac{1}{3}-\frac{1}{x+1}=\frac{20}{63}\)

=> \(\frac{1}{x+1}=\frac{1}{63}\)

=> x + 1 = 63

=> x = 62

Vậy x = 62

Sửa lại bài làm của XYZ một chút:

=> \(\frac{1}{3}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+..+\)\(\frac{1}{x}-\frac{1}{x+4}\)

=> \(\frac{1}{3}-\frac{1}{x+4}\)= \(\frac{5}{63}\div\frac{1}{4}=\frac{20}{63}\)f

so easy 32-5=27 quả

27 em nha

bai1:

a, X = 28955

b, X= 13405

c, X= 2998

d, X= 16991

bài 2:B

bài 3:C

\(\left(x+\frac{1}{2\cdot3}\right)+\left(x+\frac{1}{3\cdot4}\right)+....+\left(x+\frac{1}{15\cdot16}\right)=\frac{39}{16}\)

\(\Leftrightarrow\left(x+x+x+....+x\right)+\left(\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+....+\frac{1}{15\cdot16}\right)=\frac{39}{16}\)

\(\Leftrightarrow14x+\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+....+\frac{1}{15}-\frac{1}{16}\right)=\frac{39}{16}\)

\(\Leftrightarrow14x+\left(\frac{1}{2}-\frac{1}{16}\right)=\frac{39}{16}\)

\(\Leftrightarrow14x+\frac{7}{16}=\frac{39}{16}\)

\(\Leftrightarrow14x=2\)

\(\Leftrightarrow x=\frac{1}{7}\)

[X+1/2x3] + [X+1/3x4] + ...+[X+ 1/15x16]=39/16

tìm X

Đề bài em ghi thế này thì thầy cô khó mà hiểu đúng bài toán lắm em nhé!

con cacacacacacacacacacacacacacacacacacca

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bạn kiểm tra lại đề bài cấu (c)