\(234+\left(-117\right)+\left(-100\right)+\left(-234\right)\)

\(=117+\left(-100\right)+\left(-234\right)\)

\(=17+\left(-234\right)\)

\(=-217\)

ko bt vì tui học lơp 5

1. easier

2.the most interesting

3. the hottest

4. the most difficult

5. better

6. more exciting

7. the most intelligent

8. the oldest

9. more important

10. more expensive

11. the most famous

1. easier

2. the most interesting

3. the hottest

4. the most difficult

5. better

6. more interesting

7. the most intelligent

8. the oldest

9. more important

10. more expensive

11. the most famous

1. easier

2.the most interesting

3. the hottest

4. the most difficult

5. better

6. more exciting

7. the most intelligent

8. the oldest

9. more important

10. more expensive

11. the most famous

a) \(x^3-9x=0\)

\(\Leftrightarrow x\left(x^2-9\right)=0\Leftrightarrow x\left(x-3\right)\left(x+3\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=3\\x=-3\end{matrix}\right.\)

b) \(\left(3x+1\right)^2-16=0\)

\(\Leftrightarrow\left(3x+1-4\right)\left(3x+1+4\right)=0\)

\(\Leftrightarrow3\left(x-1\right)\left(3x+5\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-\dfrac{5}{3}\end{matrix}\right.\)

a: Ta có: \(x^3-9x=0\)

\(\Leftrightarrow x\left(x-3\right)\left(x+3\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=3\\x=-3\end{matrix}\right.\)

b: Ta có: \(\left(3x+1\right)^2-16=0\)

\(\Leftrightarrow\left(3x-2\right)\left(3x+4\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2}{3}\\x=-\dfrac{4}{3}\end{matrix}\right.\)

2. colourful: nhiều màu sắc                3. empty: trống rỗng              4. untidy: bừa bộn

5. quiet: yên lặng                  6/ noisy: ồn ào               7. full: đầy ắp

2. colourfu           

 3. empty           

 4. untidy

5. quiet                 

6/ noisy         

7. full

5 quiet

không nhớ hết từ

Bài 2: 

b: \(\Leftrightarrow x^2=10\)

hay \(x=\pm\sqrt{10}\)