Thay \(x=-1,5\) vào A, ta được :

\(A=\left(3.\left(-1,5\right)-1,2\right)-1,5:2\)

\(\Leftrightarrow A=\left(\left(-4,5\right)-1,2\right)-0,75\)

\(\Leftrightarrow A=-5,7-0,75\)

\(\Leftrightarrow A=-6,45\)

26.on

27.from - from

28.between

12. Shall we write sentences with new words?

→ I suggest that you should write sentences with new words

16. What about helping elderly people and war invalids with their chores?

→ I suggest that we should help elderly people and war invalids with their chores

18. Let’s buy a good dictionary.

→ I suggest that you should buy a good dictionary

19. How about doing some reading every day?

→ I suggest that you should do some reading every day

20. I think you should use energy-saving bulbs?

" Sybil suggests using energy-saving bulbs

21. Cecily suggests taking a rafting trip this weekend.

" Cecily suggests we should take a rafting trip this weekend.

22. Why don’t you work harder on your pronunciation?

" I suggest that we should work harder on your pronunciation

24. Why don’t you complain to the company, Peter?

" William suggested Peter should complain to the company

A.pollution /ʃ/

B.water /t/

C.contaminate /t/

D.planting /t/

\(\Rightarrow\) Chọn A

\(CuSO_4\)

\(x^3-1=-x\left(x-1\right)\)

\(\Leftrightarrow x^3-1=-x^2+x\)

\(\Leftrightarrow x^3+x^2-x-1=0\)

\(\Leftrightarrow x\left(x+1\right)-\left(x+1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\\x+1=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-1\end{matrix}\right.\)

\(CaC_2+2H_2O\text{→}Ca\left(OH\right)_2+C_2H_2\)

\(C_2H_2+2H_2\text{→}C_2H_6\)

\(C_2H_6+Cl_2\text{→C_2}H_5Cl+HCl\)

Số thập phân gồm 2 phần

\(2,15m^3=2150dm^3\)