Để \(\frac{\sqrt{x+1}}{\sqrt{x-2}}=\sqrt{\frac{x+1}{x-2}}\) là số nguyên thì \(\frac{x+1}{x-2}\) là số chính phương

Khi đó \(x+1⋮x-2\)

\(\Leftrightarrow x-2+3⋮x-2\)

\(\Leftrightarrow3⋮x-2\)

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

\(\Leftrightarrow x\in\left\{4;5;1;-1\right\}\)

Thay vào thử nha !

Ex1 : Chọn từ phát âm khác

1. A cost   B. most   C. post    Dw. roast

2. A. come   B. home   C. some  D. none

3. A. cow   B. now   C. how   D. show

4. A. name   B. classmate   C. paper   D. thank

5.A hi    B. fine   C. night   D. children

6. A. copy   B. drop   C. history   D. novel

7. A. magazine   B. mathematics   C. manage   D. watch

8. A. paint   B. same   C. pass   D. paper

9. A. nice   B. recess   C. soccer   D. center

Ex2 : chọn từ khác nghĩa

1.A. behind   B. front   C. near   D. road

2. A. came   B. bought   C. visit   D. learnt

3. A books   B. supermarket   C. students   D. classes

4. A. History   B. English   D. Maths   D. Vietnam

5. A. doctor   B. teacher   C. professor   D. student

6. A.game   B. talk   C. drink   D. eat

7. A. player   B. worker  C. painter   D. cooker

1.Make questions for the underlined past

a) She needs twelve eggs to make two cakes.

b)They drank a lot of wine at the party last night.

c) I often drink coffee in the morning .

d) Beef noodle soup is my favourite food.

e)My lemonade tastes a bit sour.

g)No,there isn't any milk in the fridge.

h)No,thanks.I love cookies,but I'm full

i)The beef broth is made by stewing cow bones.

2)Supply the correct form of the words in brackets.

a)The soup had a very ....... taste(salt)

b)She covered the cake with a ............. of sugar and whites of eggs(mix)

c)Most children enjoy eating ............ chicken and French fries(fry)

d)The pineapple was sweet and ..................(juice)

e)Meats and fish are .................... used in all Vietnamese cooking (common)

g)The chicken meat is .................. and cut into this slices (bone)

h)It took about 30 minutes of ......... and 40 minutes of baking(prepare) 

i)The sauce itself was ......... and slightly sweet(fragrance)

3.Arrange the words to make sentences.

1.kilos/how many/would/potatoes/of/like/you/?

2.but/went/I/fish/I/fishing/catch/didn't/any/

3.15/cook/for/chicken/you/over/the /low /minutes/heat/it/before/serve/

4.broken/tell/you/can/how/me/to/rice/cook/?

5.three/in/fridge/are/there/milk/the/cartons/of/.

6.has/but/egg/bread/got/he/an/hasn't/he/any/got/.

7.electric cooker/how much/in/rice/left/the/í/?

8.Vietnam/most/Pho/of/the/popular/is/one/dishes/in/.

Các bạn giúp mình đi mình đang cần gấp.Bạn nào làm nhanh mình like cho!

rewrite sentences as directed

People expect that the report will suggest some major reforms.

_ The report............................................................................................

They say that he invented the digital camera

_ He..............................................................................................

Scientists have discovered that there is water on Mars

_ Water................................

We expect the professor to arrive this morning

_ The professor......................................................................