user-avatar
thienphuc
2 năm trước
Giúp em với ạ chứng minh các biểu thức sau > hoặc < 0 B= x^2 + 2y^2 + 2z^2 + 2xy - 2yz - 2xz - 2y + 4z + 5 C= 3x^2 + 2y^2 + 4z^2 +2xy + 4yz + 4xz - 4x - 2y +5 Câu B và C sử dụng hàng đẳng thức này ạ(a + b + c)^2; (a - b + c)^2; (a + b - c)^2; (a - b - c)^2
Thích Trả lời Chia sẻ

Các câu hỏi liên quan

hơi dài nhưng mn giúp em vs!!! V. Fill in the blank with a suitable word. 1. She was cooking …………… the phone rang. 2. Would you mind …………… I smoked here? 3. Mary used …………… be a good student. 4. Yesterday was …………… hottest day during this month. 5. I sat in the first row so …………… to clearly hear his lecture. 6. she asked me when …………… depart. VI. Choose the correct word(s) to complete the sentences. 1. Would you mind (close / to close/ closing) the window? 2. The ambulance will be there (in / at / for) about 10 munites 3. We collect empty cans and bottles (in order to / so that / for) recycling. 4. John is interested ( in /on / at ) the history of Vietnam.4 5. The boy ( to read / reading / read ) the book is Ba . 6. She hasn’t finished the letter ………… (already / just / yet / never) 7. Lan’s studying hard ……. pass the final exam ( for / in order to so to , as to ) 8. It’s too cold outside. Would you mind……. the window ? ( to close, close, closing, closed ) 9. I am happy ……. all the exam (passing, pass, passed, to pass) 10 The teacher ….. to the principal is my English teacher. (talks, is talking, talking, to talk) 11. The bike ….. in Japan is USA$ 100. (making, made, is making, to make ) 12. We …dinner when the phone rang. (are having, had, have had, were having ) 13. I was having dinner ( when / while / as ) my mother was cleaning the floor. 14. We are (delight/ delighting / delighted ) that you pass your final examation. 15. Would you like ( go/ to go / going ) to the cinema tonight ? 16. Thanks ( for / to / at ) inviting me to the festival. 17. Football is (play/ playing / played ) all over the world. 18. Mai asked Hoa ( whether / to / about ) she came to Hoi An.

2018 © Loga - Không Ngừng Sáng Tạo - Bùng Cháy Đam Mê
Loga Team