3-(x+1)^2
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Ta có: \(n_{Mg}=\dfrac{6}{24}=0,25\left(mol\right)\)
PT: \(Mg+2HCl\rightarrow MgCl_2+H_2\)
Theo PT: nMgCl2 = nMg = 0,25 (mol)
⇒ mMgCl2 = 0,25.95 = 23,75 (g)
1. What are you ....of doing at weekends?
A. fond
B. keen
C. interested
D. crazy
2. The workers are.... a truck with timber,
A. unloading B. loading C. taking D. filling
3. Be quiet, please! I'm trying to.... on my homework
A. concentrate B.log
C. advise
D. bully
4. The Khmer mostly earn their living from..... and fishing
A.farming
B.hunting
C. weaving
D. gardening
5. Leaming.... can help build physical strength and improve confidence
A. martial arts B. physics C. chemistry D. custom
6. A lot of young families in Viet Nam prefer.... time doing outdoor activities together.
A. spending B. spend C. spent D. having spent
7. Hung King Temple Festival is one of...... national public holidays of Viet Nam A. O (zero article)
B.a C. the D. an
8. Peter: Jack wants to go somewhere for Mid-Autumn Festival. Trang:.....
A. Tell him to wait for a few minutes. B. He should definitely go to Hoi An. C. How about buying him an ornamental tree? D. Certainly. It meets every Friday.
9. In his free time, my younger brother is....... on taking photos and doing puzzles.
A fond B. keen C. interested D. crazy
10. Khmer men teach their children how to.... fish at an early age
A. do B. catch C. raise D. eat
11. How often do you..... notifications on Facebook? - Once a day.
A. upload B. browse C.connect D. check
12. Traditionally, the.... in a village is a place for villagers to meet or worship.
A. festival B. market C. wooden statue D. communal house
13. During Tet, the Kinh often prepare traditional.... such as banh chung and boiled chicken to worship ihn ancestors
A. decorative items B. food offerings C. spirits D. martial arts
14. According to a survey, 16% of children under 18 in the UK love .....swimming
A. gone B. go C. going D. went
15. The festival aims to remember and worship... Hung Kings, the first kings of the nation
A. O (zero article) B.a C. the Dan
16. Trang: What gift should I bring to Jane's house-warming party? Peter:.....
A. How about buying her an ornamental tree?
`3 - (x + 1)^2`
`= 3 - (x^2 + 2x + 1)`
`= 3 - x^2 - 2x - 1`
`= 2 - x^2 - 2x`
3 - (\(x+1\))\(2\)
= 3 - (\(x^2\) + 2\(x\) + 1)
= 3 - \(x^2\) - 2\(x-1\)
= - \(x^2\) - 2\(x\) + (3 -1)
= - \(x^2\) - 2\(x\) + 2