a) \(25< 5^n< 625\)

\(25=5^2;625=5^4\)

=> \(5^2< 5^n< 5^4\)

=> 2 < n < 4

=> n = 3

b) \(9\le3^n< 3.27\)

\(9=3^2;3.27=3.3^3=3^4\)

=> \(3^2\le3^n< 3^4\)

=> n = 2; hoặc n = 3

c) \(16\le8^n\le64\)

\(16=8.2;64=8^2\)

=> \(8.2\le8^n\le8^2\)

=> n = 2

\(\left(x+1\right)^3=-125\)

\(\left(x+1\right)^3=-5^3\)

\(\Leftrightarrow x+1=-5\)

\(\Rightarrow x=-6\)

\(\left(x+1\right)^3=-125\)

\(\Leftrightarrow\left(x+1\right)^3=-5^3\)

\(\Leftrightarrow\left(x+1\right)=-5\)

\(\Leftrightarrow x=-6\)

Chúc em học tốt ~~~

\(\left(x-1,2\right)^2=4\)

\(\left(x-1,2\right)^2=2^2\)

\(\Rightarrow\orbr{\begin{cases}x-1,2=2\\x-1,2=-2\end{cases}\Rightarrow\orbr{\begin{cases}x=3,2\\x=-0,8\end{cases}}}\)

(x-1,2)^2=4

=>\(\orbr{\begin{cases}x-1,2=2\\x-1,2=-2\end{cases}}\)

=>\(\orbr{\begin{cases}x=3,2\\x=0,8\end{cases}}\)

Zậy ...

\(\left(x+\frac{5}{3}\right).\left(x-\frac{5}{4}\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x+\frac{5}{3}=0\\x-\frac{5}{4}=0\end{cases}\Rightarrow\orbr{\begin{cases}x=-\frac{5}{3}\\x=\frac{5}{4}\end{cases}}}\)

My favourite hobby is reading. I enjoy reading a book when I am free. I started to do it when I was four years old. The first time I did it, I felt interested. So I kept reading. The teachers always taught me to read the difficult words. I was happy when I read a story with a happy ending. I was thrilled when I read a detective story. I enjoy reading because I to explore the imaginative world of my favourite author, J.K.Rowling who writes “ Harry Potter” . There are a lot of advantages of reading. Reading can make me relaxed and calm. I can also learn new vocabulary items. Then I can further improve my English. Moreover, it can give me an unlimited imagination, so I can write books in the future. I can learn the different cultures and customs of other countries in the world too. I read at least one hour every day. I read books by myself. I usually read it at home. I wish I could read different kinds of books because it might be very challenging.

STUDY WELL !

1b

2b

3b

4d

5b

6c

7d

8d

9 ko có đáp án đúng nếu aet là eat thì là câu b

10c