1. Tìm hàm số xác định của các hàm số sau.

a) \(y=\dfrac{x}{x^2-3x+2}\)

b)\(y=\dfrac{x-1}{2x^2-5x+2}\)

c)\(y=\dfrac{x-1}{x^3+1}\)

d) \(y=\dfrac{1}{x^4+2x^2-3}\)

e) \(y=\sqrt{x+3-2\sqrt{x+2}}\)

.  Sử dụng dạng thích hợp của từ trong ngoặc để điền vào chỗ trống. (1,5 điểm)

1.   It is ………………………. to turn off the lights when it is bright enough.             (economy)

2.   He admired her for her ………………………. performance last night.                  (amaze)

3.   I got a ………………………. result of the final examination.                                  (satisfy)

4.   The ………………………. of the environment is important.                                    (preserve)

5.   Many ………………………. were at the Games.                                           (compete)

6.   That boy did the test very ……………………….                                           (quick)

HELP ME

.  Sử dụng dạng thích hợp của từ trong ngoặc để điền vào chổ trống. (1,5 điểm).

1.   You must be ……………………  when you open the door.                          (care)

2.   We should pay attention to …………………… our environment.   (preserve)

3.   The sun was shining ……………………                                             (bright)

4.   What role does the …………………… play?                                                 (cooperate)

5.   His …………………… of stamps made us surprised.                                   (collect)

6.   They’ve never been …………………… with their study.                  (bore)

HELP ME!

Rewrite the sentences in such a way  they mean almost the same as those printed before them.

1.   I don’t intend to apologize to either of them.  =>   I have………………………………………

2.   My English friend finds using chopsticks difficult. => My English friend is………………………

3.   Surgeons have used the laser as accurate scalpels to treat cancers.=>The laser…………………………………………

4.   The gate is closed to stop the children running into the road.=> The gate is closed so that………………………

Viết tiếp câu chưa hoàn chỉnh để có cùng nghĩa với câu đã cho

. Use the correct forms of the words given.

1.   A holiday in American can be ………………… cheap.                                              (surprise)

2.   After several ………………… attempts, we have finally got it.                               (succeed)

3.   His busy work made him completely ………………… to his relatives.                  (access)

4.   Clean air make us …………………                                                                 (health)

5.   A few diseases are still ………………… in the world                                               (treat)

6.   Skilled workers are ………………… admitted                                                          (prefer)    

HELP ME !

chỉ dùng dd NaOH hãy nhận biết 6 lọ không nhõa đựng riêng từng dd sau: K2CO3, (NH)4SO4,MgSO4, Al2(SO4)3, FeSO4, Fe2(SO4)3.

vì sao trong vôi bột có đủ 3 thành phần CaO, Ca(OH)2, CaCO3, hãy giải thích?

help me!