cho mình hỏi gấp là hệ số của một đơn thức có được có số mũ ko? ví dụ như 9mũ 2 nhân x.... thì 9 mũ 2 có phải hệ số ko?

cho hình chóp S.ABCD có đáy là tam giác vuông cân tại B, AB=2, các cạnh bên đều bằng 2. Tính thể tích của khối cầu ngoại tiếp hình chóp S.ABCD=?

. My mother (fry)________ eggs for breakfast every morning. Kate phoned me last night. She is on holiday in France. She (have) ...................... a great time and doesn’t want to come back 2. John (try)……..hard in class, but I (not, think) ………..he'll pass. 3. You (speak) …………English? 4. I (lend)……..my penknife to someone, but I can't remember who it was now. 5. It’s 12 o’clock, and my parents (cook) ………………….. lunch in the kitchen. 6. They (buy).....................a new car two days ago? 7. She…….( not, study) English tomorrow. 8. Your brother (sit) ………………….. next to the beautiful girl over there at present? 9. When my father was reading newspaper, the phone…….( ring). 10. The bank ……….(close)at four o'clock

1, Cho tam giác ABC vuông tại A, AB=12cm, AC=16cm, đường phân giác góc A cắt BC tại D a, Tính BC, BD, CD b, Kẻ đường cao AH. TÍnh AD, AH, HD 2, Cho tam giác ABC cân tại A có AB=AC=5cm, BC=6cm. Phân giác góc B cắt AC tại M, phân giác góc C cắt AC tại N a, chứng minh: MN//BC b, Tính AM, MC, MN

(x+20)(y-1) = xy và (x-10)(y+1) = xy Giải hộ mình bài này với!!! Giải hệ phương trình :

tìm số tự nhiên x ,biết a, 2 mũ x .4 =128 b, x mũ 15 =x c, 16 mũ x < 128 d, 5 mũ . 5 mũ x +1 < hoặc =100...0 chia 2 mũ 18 (t ừ 100 đến 0 có 18 c/s 0) e, 2 mũ x . ( 2 mũ 2) tất cả mũ 2 = ( 2 mũ 3 ) tất cả mũ 2 f, (x mũ 5 ) tất cả mũ 10=x

Các cao nhân giúp em câu 2_3_4 với

a) (-2).(-6)2+3.(-2)3-62 b) (-6).4.(-7).(-25) C) (-85)+(-105)+62 d) (-8).7.(-3).(-5)

Stories about how people somehow know when they are being watched have been going around for years. However, few attempts have been made to investigate the phenomenon scientifically. Now, with the completion of the largest ever study of the so- called staring effect, there is impressive evidence that this is a recognizable and (55) _____ sixth sense. The study involved hundreds of children. For the experiments, they sat with their eyes (56) _____ so they could not see, and with their backs to other children, who were told to either stare at them or look away. Time and time again the results showed that the children who could not see were able to tell when they were being stared at. In a (57) _____ of more than 18, 000 trials (58) _____ worldwide, the children correctly sensed when they were being watched almost 70% of the time. The experiment was repeated with the (59) _____ precaution of putting the children who were being watched outside the room, (60) _____ from the starters by the windows. This was done just in case there was some (61) _____ going on with the children telling each other whether they were looking or not. This (62) _____ the possibility of sounds being transmitted between the children. The results, though less impressive, were more or less the same. Dr Sheldrake, the biologist who designed the study, believes that the results are (63) _____ enough to find out through further experiments precisely how the staring effect might actually (64) _____. 55. A. genuine B. accepted C. received D. sure 56. A. shaded B. covered C. masked D. wrapped 57. A. sum B. collection C. total D. mass 58. A. worked over B. carried out C. carried on D. worked through 59. A. added B. attached C. connected D. increased 60. A. parted B. seperated C. split D. divided 61. A. pretending B. lying C. deceiving D. cheating 62. A. prevented B. omitted C. evaded D. ended 63. A. satisfying B. persuading C. concluding D. convincing 64. A. set out B. be looked at C. come about D. be held up giúp mình với ạ mình cảm ơn

cho tứ giác ABCD có AC vuông góc với BD, AC= 12cm, BD=20 c. Tính diện tích của tứ giác đó có hình vẽ