tại sao câu 13 lại chọn B chứ k phải A??

Chứng minh : 1)H= -4$x^{2}$-6x-4 2)K= -$\frac{1}{2}$$x^{2}$-x-1 3)L= -$\frac{1}{3}$$x^{2}$+2x-5 Luôn âm với mọi x

6x^2 -2x (3x+3/2) Tặng đ nhưng pklm đúng

Nhiệm vụ chủ yếu của người học sinh là... tích cực tham gia các hoạt động tập thể và hoạt động xã hội để phát triển toàn bộ nhân cách.Trong dấu"..."đó là gì? A.Tu dưỡng đạo đức , học tập tốt B.Chăm ngoan, học giỏi C.Tích cực học tập, tu dưỡng đạo đức D.Tích cực rèn luyện, tu dưỡng đạo đức

You (should/eat) less seafood 🦑 - look at the icon and guess what animal is this

các bạn viết cho mk một bài nói tiếng anh về chủ để SOURCES OF ENERGY vs mk cảm ơn(ko lấy trên mạng nha)

V. Give the correct forms of the verbs in parentheses. 1. My mother is saving money because they ( buy) ……………… a new house next year. 1. She is preparing her trip now. She (visit) ………………………… her friends tonight. 2. What ..………you (do)………….. this Sunday? - I (visit).............................. my grandparents. 3. Excuse me, I ......................... (look) for a phone book. Is there one near here? 4. She usually....................................dinner for the family. (cook) 5. What ……. your plan ( be ) this summer vacation ? I (travel ) ………….. around the world. 6. Listen! Can you hear those people next door? They ......................... (shout) at each other again. 7. The children................basketball now. (play). They always ( play ) …….. it after school. 8. Why ......... you ( buy ) …….. a lot of flour? Because I ( make ) …………… a big birthday cake for my son tonight. 9. The boys...................................a play for their school show on T.V at the moment. (rehearse) 10. They......................their mother with the housework everyday. (help)

Cho hàm số y= (x^3/3)-mx^2-3mx+4. Để hàm số đạt 3 cực trị tại x(1);x(2). Để thỏa mãn: x(1)^2 +2mx(2) +9m m^2 ______________________+______________________ m^2 x(2)^2 +2mx(1)+9m Thì m thuộc khoảng nào

84. Would you mind ....................... your address on the back of this check? A) write B) to write C) writing D) written 85. I don’t enjoy .................... to the dentist’s. A) go B) to go C) going D) goes 86. I don’t regret .......................... her what I thought even if it upset her. A) to tell B) told C) tell D) telling 87. Remember ........................ Katie my greeting card when you see him. A) give B) to give C) giving D) gave 88. My friends has given up ...................... and prefers ..................... pork. A) drink/ eat B) to drink/ eating C) drinking/ eating D) drank/ eat 89. I had to ask the boys .......................... ................................. billiards all the day. A) to stop/ playing B) to stop/ to play C) stopping/ playing D) stops/ to play 90. My teacher promised ................... me .......................... for my next examination. A) help/ prepare B) to help/ prepare C) helping/ to prepare D) helped/ preparing 91. I would like him ......................... ............................ more English lessons. A) to start/ take B) to start/ taking C) starting/ take D) starting/ taking 92. I hate .......................... ................. aloud without ....................... the new words. A) practise/ reading/ learn B) to practise/ to read/ to learn C) to practise/ reading/ learning D) practises/ reading/ to learn 93. She doesn’t want you .......................... to her arriving. A) mention B) to mention C) mentioning D) mentions 94. Did you manage .......................... ..................... these parcels alone? A) finishing/ to pack B) finishing/ packing C) to finish/ to pack D) to finish/ packing 95. Can someone .................... me how ............. into film from the camera’s pictures? A) show/ change B) to show/ to change C) showing/ change D) show/ to change 96. I’ll try ........................................... such a foolish thing again. A) not to cause B) to not cause C) not causing D) to cause not 97. Susan has decided ......................... her friends ...................... as she pleases. A) allow/ do B) to allow/ to do C) deciding/ do D) deciding/ doing 98. Everybody would like ................................ to a higher position. A) promote B) promotes C) promoting D) to promote 99. He climbed over the wall without ............................ by anybody. A) seeing B) to see C) being seen D) to be seen 100. I remember ................................ a toy car on my fifth birthday. A) to be given B) being given C) to give D) giving 101. They always try .................. ................ the bridge as they promised before. A) to postpone/ to build B) postpone/ build C) to postpone/ building D) postponing/ built 102. I can’t help .......................... for her acceptance. A) to wait B) waiting C) wait D) waited 103. Don’t be afraid of .......................... that animal. A) touch B) touches C) touching D) to touch 104. I am accustomed to ......................... on my own. A) living B) to live C) live D) lives 105. They are looking forward to ...................... your news. A) hear B) to hear C) hearing D) heard 106. American women have got used to .................independently recently. A) live B) to live C) living D) lives 107. We won’t let you............... what we are going to do with him. A) know B) to know C) knowing D) known

Cho Fe phản ứng với dung dịch H2SO4 đặc, nóng thu được khí SO2 duy nhất và dung dịch chứa 8,28 gam muối. Biết số mol Fe phản ứng bằng 37,5% số mol H2SO4 phản ứng. Tính khối lượng Fe đã phản ứng. KHÔNG CHÉP MẠNG, GẤP