giúp mình với nha!

Tìm x, biết:
a) 3x - 1/4 = 7/5
b) 2x - 3/4 = 1/2
c) 1 + 3x = -5
d) 5/8 + 3/8 x = 9/2
e) 1/2 x - 1/3 = 4/9
f) 4/5 x - 19/5 = -3/5
g) 1,5 x - 7/3 x = 1,5 - 2/3
h) 18/5 - 5/4 x = -1/6
i) 3/5 x - 2/7 = 4/5
j) 2/3 + 7/4 : x = 5/6
k) 2/3 + 1/3 : x = 3/5
l) 5/7 : x - 2/5 = 1/3
m) x : 16/7 + 1/8 = 4/3
n) 1/3 + x : 1/3 = 1

A) $\frac{5}{9}+\frac{2}{7}$
B) $\frac{5}{13}÷\frac{2}{7}$
C) $4÷\frac{1}{5}$
D) $\frac{5}{7}-\frac{1}{9}+4\times \frac{3}{2}$
Bài 2 tính nhanh
A)16/81+5/13+65/81+8/13
B)4/97×21/19-4/97×2/19

21. He turned …… the light so as not to waste electricity.
A. off B. of C. on D. down
22. My father tells me to give …… smoking.
A. up B. off C. of D. out
23. Anne smokes a lot. …… .
A. So her mother does B. So does her mother
C. Does her mother too D. Too her mother does
24. I haven’t seen Jenny …… .
A. for a long time B. in the last time C. since long D. lastly
25. Are these the books …… you have been looking for?
A. which B. who C. whom D. whose
26. Keiko has $100. Betty has$75. Betty has less money than Keiko.
A. more money than B. not as much money as
C. the same money as D. a lot of money
27. Have you fed the chickens yet? In the passive voice, this should be:
A. Has somebody fed the chickens yet? B. Have the chickens fed yet?
C. Have the chickens been fed yet? D. Have you had the chickens fed yet?
28. nice surprise / receive / your letter.
A. to receive your letter it is a nice surprise. B. Receiving your letter it is a nice surprise.
C. It is a nice surprise to receive your letter. D. It is a nice surprise when receiving your letter.
29. I / school / five days / week / favorite subjects / Math / English.
A. Despite I go to school five days a week and my favorite subjects are Math and English
B. I go to school five days a week and my favorite subjects are Math and English.
C. I go to school five days in a week so that my favorite subjects are Math and English.
D. I go to school five days a week with my favorite subjects are Math and English.
30. There / more visitors / March / April
A. There were more visitors in March than in April.
B. There were more than visitors in March and in April.
C. There were as many as visitors in March and in April.
D. There were visitors in March more than in April.
31/ Vietnam’s population …………. 80 million in 2004 .
A. reduced B. increased C. reached D. rose
32/ The air………….. the earth is becoming thinner.
A. surrounding B. rounding C. involving D. floating
33/ ………... energy is the energy that we get from the sun
A. wind B. tidal C. hydro D. solar
34/ The sun is many times ………… the earth.
A. bigger than B. bigger C. as big D. big as
35/ Mercury is the smallest among the planets …………. the sun.
A. of B. for C. with D. on
36/ ……………. a kind of everlasting energy, solar energy may be the solution to our crisis
A. Because B. Since C. As D. With
37/ Students ………. universities may have many difficulties in finding good study method.
A. enter B. entering C. that enter D. who enter
38/ your house has ………… nice furniture.
A. such B. such a C. so D. towards
39/ …………. tired, I went to bad early.
A. To feel B. Felt C. Feeling D. Having
40/ You hardly ever believe him and …………………
A. so do I B. neither do I C. I do either D. I believe him
41. If Hoa ____ rich, she would travel around the world.
A. is B. was C. were D. been
42. Ba ____ a new bicycle recently.
A. bought B. buying C. buy D. has bought
43. Nam ____ speaks Chinese but also speaks Japanese.
A. not only B. so C. only D. can
44. It is raining very hard ____ we can't go camping.
A. so B. so that C. more over D. however
45. Miss Hoa ____ sing very well is Nam's mother.
A. which B. whom C. who D. where
46. Hung enjoys ____ fishing and boating.
A. to go B. go C. going D. went
47. She asked me where I ____ from.
A. come B. coming C. came D. to come
48. The Ao Dai is the traditional dress of ______ women.
A. Chinese B. Vietnamese C. Japanese D. English
49. She loves to watch the star ____ night.
A. in B. at C. on D. from
50. We must finish our project _____.
A. on time B. in time C. yesterday D. time
51. Milk bottles can be _____________________after being cleaned.
A. recycled B. reused C. broken D. reduced
52. It was raining heavily __________________we arrived home.
A. while B. until C. because D. when
53. She asked me ____________________I liked eating chocolates.
A. if B. and C. that D. but
54. You look _____________________than last year.
A. much tall B. more tall C. much taller D. more taller
55.What ____________________advice she gave us !
A. so good B. such good C. a good D. good
56.My dog as well as my cats ____________________twice a day.
A. eat B. eats C. has eaten D. have eaten
57. When I came into the class, I realized I knew ______________________.
A. them all B. all them C. they all D. all of they
58. Do it right now, ___________________ ?
A. do you B. aren’t you C. will you D. don’t you
59. We ____________________for her for ten minutes.
A. wait B. waited C. are waiting D. have been waiting
60. His father is not interested in tennis and ____________________.
A. he doesn’t, either B. so doesn’t he
C. neither does he D. neither is he
61. The little girl wasted half an hour ___________________for her picture book.
A. look B. looking C. to look D. looked
62. ____________________does it take you to do the washing ?
A. How fast B. What time C. How long D. How often
63. Your hair is long. Are you going to _____________________ ?
A. have it cut B. have cut it C. be cutting it D. have it cutting
64. Would you like tea or coffee? – I ____________________drink tea than coffee.
A. would like B. would prefer C. would rather D. would wish
65. It is high time you ______________________more attentive in class.
A. are B. were C. must be D. have been
66. He was _____________________that we turned off the TV set immediately.
A. so bad singer B. such bad singer C. such bad a singer D. so bad a singer
67. I wish you _______________________that! It’s really annoying habit.
A. won’t do B. couldn’t do C. wouldn’t do D. don’t do
68. “I’m sorry about that!” – “______________________!”
A. That’s right B. Of course C. It’s OK D. You’re welcome
69. Not until 2008 ______________________across the river.
A. the first bridge was built B. the first building of a bridge was
C. built the first bridge D. was the first bridge built
70. Excuse me! I’m learning my lesson. _________________turning down your stereo a bit ?
A. Would you please B. Would you mind
C. Could you D. Would you like

14,4 :12
125,07:11

chứng tỏ biểu thức sau không phụ thuộc vào x A=(x+1).(x^2+x+1)-(x-1).(x^2+x+1)

chứng tỏ biểu thức sau không phụ thuộc vào x A=(x+1).(x^2+x+1)-(x-1).(x^2+x+1)