Cho e xin cách giải hình câu này với ạ

Bạn hãy điền số thích hợp vào ô trống. Nga lập danh sách số học viên của các lớp tại một trung tâm Năng khiếu như sau: (xem hình) Biết trung bình mỗi lớp có 18 học viên. Vậy số học viên lớp Trống là: ...(1) học viên.

Hoà tan hoàn toàn 27,4 gam hỗn hợp M 2 CO 3 và MKCO 3 bằng 500 ml dung dịch HCl 1M thoát rà 6,72 lít CO 2 (đktc). Để trung hoà axir dư phải dùng 50 ml NaOH 2M. Tìm 2 muối và % khối lượng của các chất có tron hỗn hợp.

Hòa tan 1 kim loại bằng dung dịch HCl 10% vừa đủ thì thu được dung dịch muối clorua có nồng độ 11,93%.  Tìm kim loại.

CO2 + NaOH ---> NaHCO3 CO2 + 2NaOH ---> Na2CO3 + H2O Kết luận : - Nếu nNaOH/nCO2 ≤ 1 => Sản phẩm tạo ra 1 muối axit NaHCO3 - Nếu nNaOH/nCO2 ≥ 2 => Sản phẩm tạo ra 1 muối trung hoà Na2CO3 - Nếu 1 < nNaOH/nCO2 < 2 => Sản phẩm tạo ra 2 muối: NaHCO3 và Na2CO3 Giải thích hộ mình cơ sở phản ứng trong 3 TH trên kia với ạ. Vì sao với điều kiện đó lại tạo ra muối như vậy ạ? Mình cảm ơn !

Câu 2. Cho ∆ABC (Â = 90°) , AB = 12 cm, BC = 13cm. Tính AC, đường cao AH, các đoạn thẳng BH, CH và diện tích của tam giác.

Tính nhanh `1.2.3+2.3.4+3.4.5+...+98.99.100`.

Bài 1.Phân tích thành nhân tử bằng cách đổi biến để đưa về dạng tam thức bậc hai đối với biến mới a,6x⁴-11x²+3 b,(x²+x)²+3(x²+x)+2 c,x(x+1)(x+2)(x+3)+1 d,x²-7xy+12y² e,x²-2xy+y²+x-3y-10 Bài2.Phân tích thành nhân tử a,x⁵+x+1 b,x⁷+x²+1 Bài 3.Phân tích ttthanhf nhân tử a,x⁴+4 b,x⁴+64 c,64x⁴+1 d,81x⁴+4

60 điểm nhé mình cần gấp trong 30p ạ

Read this passage and then match the time with the correct events This is the passage: FILM FRIGHT: History of Horror Films: The first motion pictures were made in the 1890s. They were usually very short and simple. Some were only thirty seconds long! People were fascinated with moving images. In 1910, Thomas Edison made the movie Frankenstein. It was only sixteen minutes. It terrified moviegoers, though. In the 1920s, a horror movie revolution began. People made numerous silent horror films. Movie studios made many popular monster movies from 1920 to 1950. In 1931, Universal Studios released Dracula and Frankenstein. These films were two of the most successful horror movies of the time. The studios also made movies about other characters. These characters included the Wolf Man, the Invisible Man, and the Creature from the Black Lagoon. Studio Monsters: The studios made several movies about the Frankenstein monster during this time. The original one tells about mad Dr. Frankenstein. He creates a monster from body parts. Then he brings it to life. The next movie was The Bride of Frankenstein. The monster forces Dr. Frankenstein to build him a monster wife. In The Son of Frankenstein, Frankenstein’s son wakes up the monster. The terror begins all over again. The Ghost of Frankenstein includes a monster more terrible than ever. In the 1940s, studios began teaming up movie monsters. Frankenstein Meets the Wolf Man is an example. It joins the story of Frankenstein’s monster with the story of the Wolf Man. In The Wolf Man, Lawrence Talbot tries to save a woman from awerewolf. Talbot kills the werewolf. But he is bitten by it. At the next full moon, Talbot turns into the Wolf Man. The Men Who made the Monsters: Jack Pierce was a makeup artist. He created the monsters in Frankenstein Meets the Wolf Man. Pierce used glue and animal hair to make the Wolf Man. The makeup was very uncomfortable. The actors had to sit still for many hours. It could be a grueling experience. The results were spectacular, though. John P. Fulton was a cameraman. He worked on Frankenstein Meets the Wolf Man. Fulton used stop-motion photography. This process takes a very long time. Fulton used this technique to show Talbot transforming into a werewolf. First he filmed the actor without makeup. Then he stopped the camera. Jack Pierce applied the first layer of makeup. Then Fulton filmed for a few more seconds. Fulton and Pierce repeated this process many times. Fulton put all the pieces together. On screen, Talbot turned into the Wolf Man. The transformation on film took ten seconds. The actual process took about six hours! The Legacy: By the 1950s, U.S. movie studios stopped making these types of monster movies. New horror movies began to take their place. The classic monsters were not forgotten, though. In 1974, Mel Brooks and Gene Wilder made Young Frankenstein. They filmed it where the original Frankenstein series was filmed. Their movie is a comedy. It makes fun of the old Frankenstein films. It also honors them. Frankenstein Returns: In 1994, Kenneth Branagh made Mary Shelley’s Frankenstein. His movie follows the same basic plot as Shelley’s novel. In this movie, Frankenstein’s monster is not a flat-headed, growling monster. It is an intelligent and sensitive creature. Stamp of Approval: The movie monsters of the 1930s and ’40s have had a lasting effect on popular culture. In 1997, the U.S. Postal Service made the Classic Movie Monsters postage stamps. These stamps also honored the work of makeup artist Jack Pierce. The work of these horror movie pioneers helped make the monsters popular. Because of them, Frankenstein’s monster and the Wolf Man continue to be popular today.