giải phương trình sin(x-pi/3)*sin(x+pi/3) + căn cos(x+pi/3) +2=0

Cho tam giác ABC với các đường cao AA1, BB1, CC1. Chứng minh rằng các hình chiếu vuông góc của A1 lên AB, AC, BB1, CC1 thẳng hàng

nêu công thức và cách dùng dấu hiệu nhận biết của 3 thì tương lai tiếp diễn , tương lai hoàn thành ,tương lai hoàn thành tiếp diễn

Giúp mk II. Supply the correct tense of the verbs: 1. The weather ( be )……………………. very bad yesterday. 2. My mother always ( get ) …………………… up early. 3. Tom ( see ) ……………………his classmates at the party tomorrow. 4. He ( give ) ……………………me the letter a few minutes ago. 5. They ( make ) …………………… a lot of furniture next month. 6. Peter and Alice ( learn ) …………………… French for two years. 7. You ( not finish ) your …………………… homework yet. 8. My friend ( never see ) …………………… that sight. 9. My uncle ( live ) ……………………in HCM city since last year. 10. He always ( stay ) …………………… in bed late on Sunday morning. 11. Peter and Daisy ( be ) …………………… born in 1978. 12. My sister always ( wash ) …………………… her hands before meals. 13. Look! The dog ( run ) ……………………after him. 14. Smith and Bobby ( read ) …………………… books at this moment. 15. Tom ( repair ) …………………… his bicycle last Friday. 16. Mary and I ( not watch ) …………………… TV last night. 17. I ( just buy ) ……………………a new shirt. 18. Where you ( go ) …………………… last night ? - I ( go ) …………………… to the cinema.

Làm câu nào cũng đc trừ câu 5 ra , giúp nhanh ạ ít nhất làm 3 câu

Phân tích đa thức thành nhân tử a/ $9x^{2}$- $4x^{2}$$y^{2}$+$12xy$-$6x$-$8$ b/$x^{3}$+ $3x^{2}$$y$- $4y^{3}$

Giúp mik nha (nếu đc nêu từ khóa, cách dùng và thì luôn nha)

với mọi x thuộc z ta có a)N^3-19N LÀM THEO CÁCH LỚP 8 NHANH LENNNNNNNNNNNNNNNN

Rewrite:It took him 2 hours to water the trees(spent)->... They have learnt English from 4 years ->They started...

1. You have to finish this work on time.  This work ......................................................................................................................... 2. Must the test be finished before ten?  Must they.......................................................................................................................... 3. How long is it since they last saw that film?  When did.......................................................................................................................... 4. When was this car bought? (turn into active)  When ................................................................................................................................