Tìm các số tự nhiên x, y, z thỏa mãn: $2^{x}$.$3^{y}$ = 1 + $5^{z}$

Giúp mình bài dưới và mấy câu khoanh ở trên với ạ.

cho tam giác ABC biết AB= 2cm, BC=7cm và cạnh AC là một số tự nhiên lẻ, tìm chu vi tam giác ABC nhanh, ngắn gọn mik cho ctlhn

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Cho 1,6g CuO tác dụng với 100g dd H2SO4 20% tính nồng độ % các chất dư có trong dd sau PƯ

change the sentences into the passive 1. The Temple of Literature is regarded as the first university in Vietnam. → 2. His father bought a picture of the One Pillar Pagoda last year. → 3. Thousands of people visit the Hung Kings’ Temple every day. → 4. By whom was the Imperial Academy built? → 5. People can see Khue Van Pavilion symbol on street signs in Hanoi. → 6. Vietnamese people use Khue Van pavilion as a symbol of Hanoi. → 7. What surrounds the Temple of Literature? → 8. In 1994, Ha Long Bay was recognised by UNESCO as a World Heritage Site

Có bao nhiêu số tự nhiên có 4 chữ số? Có bao nhiêu số chẵn có 3 chữ số?

Many people still believe that natural resources will never be used up. Actually, the world’s energy resources are limited. Nobody knows exactly how much fuel is left. However, we also should use them economically and try to find out alternative sources of power. According to Professor Marvin Burnham of the New England Institute of Technology, we have to start conserving coal, oil and gas before it is too late; and nuclear power is the only alternative. However, many people do not approve of using nuclear power because it’s very dangerous. What would happen if there was a serious nuclear accident? Radioactivity causes cancer and may badly affect the future generations.The most effective thing is that we should use natural resources Marvin Bras economical as possible. 1.How much fuel left? A. there is a lot of fuel B. Let's use it as much as we would like C. No one knows exactly D. It will never be used up 2. According to professor Mavin Burnham,..... A. solar power is the only alternative B. we have to save coal, oil, and gas C. A and B are incorrect D. A and B is correct 3. Radioactivity from nuclear power..................... A. alters a new kind of energy B. is necessary to cure diseases C. can have good effects on the future generations D. causes caner and has bad effects on the future generations 4. We should use coal, oil, and gas................,, A. as much as possible B. Carelessly C. as economically as possible D. all are incorrect 5. According to the passage, using nuclear power is.............. A. interesting B. dangerous C. safe D. cheap

1) Một chất điểm thực hiện đồng thời hai dao động điều hòa cùng phương cùng tần số với phương trình: x1=A1. cos(ωt+ π/6) ,x2=A2. cos(ωt+phi)cm. Phương trình tổng hợp của con lắc có dạng x=A.cos( ωt+π/3)cm. Thay đổi giá trị A1 để A đạt giá trị lớn nhất tìm giá trị A đó

1 . tả buổi tối gia đình em quây quần bên nhau . 2. tả cây ăn quả . 3. tả hồ gươm . bạn nào chọn đề nào thì ghi nha