1. Rebecca always loves hiking and other outdoor activities.

2.  Fruit is convenient source of vitamins and energy.

3. She doesn't like fish because she hates the bones.

4.  Do you think I should wake up at the usual time on Sundays?

5.  Watching TV too much isn't good for your eyes.

6. Many towns are full of shopping malls and fast food restaurants.

7. We should keep healthy by eating well and exercising regularly.

8. Nutrition and exercise are essential for fitness and health.

a) `x^4+x^3+x^2+x=x^3(x+1)+x(x+1)=(x+1)(x^3+x)=(x+1).x.(x^2+1)`

b) `x^3+2x^2-x-2=(x^3-x)+(2x^2-2)`

`=x(x^2-1)+2(x^2-1)`

`=(x+2)(x^2-1)`

`=(x+2)(x-1)(x+1)`

c) `x^2-xy-x+y`

`=(x^2-xy)-(x-y)`

`=x(x-y)-(x-y)`

`=(x-y)(x-1)`

d) `xy+4-x^2+2y`

`=(xy+2y)+(4-x^2)`

`=y(x+2)+(2-x)(x+2)`

`=(x+2)(y+2-x)`

e) `xy+y-2(x+1)`

`=y(x+1)-2(x+1)`

`=(x+1)(y-2)`

f) `2(x+y)+ay+ax`

`=2(x+y)+a(x+y)`

`=(x+y)(a+2)`

will/can/should đều được á, theo ngữ cảnh của câu thì should hợp hơn will

1. A

2. C

3. B

4. A

5. D

6. A

7. C

8. C

9. C

10. D

Số thích hợp: `54`

Quy luật: số đứng sau gấp `3` lần số đứng trước. 

`sin^2 30^@ + tan 40^@ . tan 50^@ . cot30^@ .cos 30^@ .cos 60^@`

`=sin^2 30^@ + (tan40^@ . cot 40^@ ). cot 30^@ . cos30^@ . cos60^@`

`=(1/2)^2 + 1 . sqrt3 . sqrt3/2 .1/2`

`=1/4 + 3/4`

`=1` 

ĐKXĐ: `12x+18>=0 <=> x>= -3/2`

I. Choose the best answer

1. His mother is short ………….. his sister is so tall.

A. although                  B. but                       C. and                      D. despite

2. Environmental ………….. is a serious problem facing mankind today.

A. polluted                   B. pollute                  C. pollution               D. polluting

3. In order to save money, we should use public transport ………….. motorbikes.

A. instead of                 B. except                  C. besides               D. along with

4. I’m really ………….. that people have spoiled the environment by littering garbage everywhere.

A. disappointing           B. disappointed         C. disappoint           D. disappointment

5. Lan suggested ………….. to the cinema tonight.

A. go                             B. to go                     C. went                    D. going

6. I’m ………….. that you are working hard.

A. pleasant                    B. pleased                 C. pleasure            D. pleasing

7. If the rice paddies ………….. polluted, the rice plants will die.

A. is                               B. was                        C. are                    D. were

8. Lan visited London last summer. She stayed in a hotel and her friend, Mary came to pick her ………….. to go sightseeing.

A. up                              B. over                        C. out                    D. of

9. The boy ………….. put up the Christmas decoration is my brother.

A. who                            B. whose                    C. whom               D. which

10. She has never learned ………….. to play the violin.

A. how                            B. what                       C. why                  D. whether

11. Owning a car is too costly, ………….. I traveled by bus instead.

A. so that                        B. so                           C. that                  D. since

12. The details should ………….. carefully.

A. is checked                  B. check                     C. was checked    D. be checked

13. If Mary doesn’t improve in math, we ………….. have to find a tutor for her.

A. will                              B. can                          C. should             D. would

14. The journey to the village is very ………….. .

A. interested                   B. interesting               C. disinterested    D. interest

15. I don’t like using the internet because it has some …………..

A. benefits                      B. advantages              C. limitations        D. disadvantages

a) `A+B=x^2y+2x^3-xy^2+5+x^3+xy^2-2x^2y-6`

`=(x^2y-2x^2y)+(2x^3+x^3)+(-xy^2+xy^2)+(5-6)`

`=3x^3-x^2y-1` 

``

b) `B=A+C`

`<=>C=B-A`

`<=>C=x^3+xy^2-2x^2y-6-(x^2y+2x^3-xy^2+5)`

`<=>C =x^3+xy^2-2x^2y-6-x^2y-2x^3+xy^2-5`

`<=> C=(x^3-2x^3)+(xy^2+xy^2)+(-2x^2y-x^2y)+(-6-5)`

`<=>C=-x^3+2xy^2-3x^2y-11`

`7/3 x^3 y^2 : M =7xy^2`

`=> M = 7/3 x^3 y^2 : 7xy^2`

`=> M= (7/3 : 7) . (x^3 :x) .(y^2 :y^2)`

`=> M= 1/3x^2 `