Hai người thợ cùng làm chung một công việc trong 8 ngày thì hoàn thành 2/3 công việc. Nếu làm 1 mình để hoàn thành công việc đó thì người thứ nhất làm nhanh hơn người thứ hai 10 ngày. Hỏi thời gian mỗi người làm một mình xong cả công việc
65. Phân tích đa thức thành nhân tử
a) \(ab\left(a+b\right)-bc\left(b+c\right)+ac\left(a-c\right)\)
b) \(a\left(b^2+c^2\right)+b\left(c^2+a^2\right)+c\left(a^2+b^2\right)+2abc\)
c) \(\left(a+b\right)\left(a^2-b^2\right)+\left(b+c\right)\left(b^2-c^2\right)+\left(c+a\right)\left(c^2-a^2\right)\)
d) \(a^3\left(b-c\right)+b^3\left(c-a\right)+c^3\left(a-b\right)\)
e) \(a^3\left(c-b^2\right)+b^3\left(a-c^2\right)+c^3\left(b-a^2\right)+abc\left(abc-1\right)\)
64. Phân tích đa thức thành nhân tử
a)\(a\left(b^2+c^2+bc\right)+b\left(c^2+a^2+ac\right)+c\left(a^2+b^2+bc\right)\)
b) \(\left(a+b+c\right)\left(ab+bc+ca\right)-abc\)
c) \(a\left(a+2b\right)^3-b\left(2a+b\right)^3\)
Exercise 1: Read and answer the questions
Emma Watson is a British actress, model, and activist. She has been widely known not only as a talented young actress, but also a humanitarian. She rose to fame after having her first professional acting role as Hermione Granger in the Harry Potter film series from 2001 to 2011. Other successness include her acting in The Perks of Being a Wallflower and The Bling Ring. Besides her movie career, she has also earned a bachelor's degree in English literature. She was appointed the UN Women Goodwill Ambassador in July 2014. At the age of 26, she has dedicated he efforts towards the empowerment of young women ad promotion of gender equality worldwide. Emma shared, "I still have so much to learn, but as I progess I hope to bring more of my individual knowledge, experience and awareness to this role."
1. What nationality is Emma Watson?
2. What role turned Emma Watson into a famous actress?
3. What is her highest qualification?
4. What role has she undertaken since 2014?
5. Which gender has Emma promoted development for?
Complete the following words sentences with the past form of the verbs in brackets
close | ask | laugh | jump | rescue |
start | stop | walk | try |
study |
1. My father ............ Math at university.
2. We were very tired so we ............ walking.
3. I ............ to pick the bag up, but it was very heavy.
4. The firemen ............. the woman from the burning house.
5. The cat ............ up into the tree.
6. After the film, we .......... home.
7. It was very cold so we ............ the window.
8. You are late! The lesson ............ ten minutes ago.
9. The teacher .......... a lot of questions yesterday.
10. The programme was very funny, we ...... a lot.