9) \(3x^2+5x-8=0\)

\(\left(3x^2+8x\right)-\left(3x+8\right)=0\)

\(x\left(3x+8\right)-\left(3x+8\right)=0\)

\(\left(x-1\right)\left(3x+8\right)=0\)

\(\Rightarrow x-1=0\) hoặc \(3x+8=0\)

\(x=1\) hoặc \(x=-\dfrac{8}{3}\)

11) \(-5x^2+3x+2=0\)

\(-\left(5x^2-5x\right)-\left(2x-2\right)=0\)

\(-5x\left(x-1\right)-2\left(x-1\right)=0\)

\(\left(-5x-2\right)\left(x-1\right)=0\)

\(\Rightarrow-5x-2=0\) hoặc \(x-1=0\)

\(x=-\dfrac{2}{5}\) hoặc \(x=1\)

13) \(2x\left(3x-5\right)=10-6x\)

\(2x\left(3x-5\right)+\left(6x-10\right)=0\)

\(2x\left(3x-5\right)+2\left(3x-5\right)=0\)

\(\left(2x+2\right)\left(3x-5\right)=0\)

\(\Rightarrow2x+2=0\) hoặc \(3x-5=0\)

\(x=-1\) hoặc \(x=\dfrac{5}{3}\)

2) \(2x^2-2x=\left(x-1\right)^2\)

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

\(x^2=1\)

\(\Rightarrow x=1\) hoặc \(x=-1\)

4) \(x^2-4=2\left(x-2\right)^2\)

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

\(\left(x-2\right)\left[\left(x+2\right)-2\left(x-2\right)\right]=0\)

\(\Rightarrow x-2=0\) hoặc \(\left(x+2\right)-2\left(x-2\right)=0\)

\(x=2\) hoặc \(-x+6=0\)

\(x=2\) hoặc \(x=6\)

1. Mary is reading books in the classroom.
2. Tom always watches TV after dinner.
3. How often do you play computer game?
4. He often plays table tennis with his teacher after school.
5. I often surt to the Internet before I go to bed.

10. A
11. True
12. False
13. True
14. False
15. B
16. B

1. C
2. B
3. C
4. D
5. C
6. A
7. A
8. C
9. C

11. A
12. D
13. B
14. A
15. A
16. D
17. A
18. C

1. C
2. A
3. C
4. B
5. C
6. D
7. B
8. B
9. D
10. B

A. 40/11

Giải thích: \(\dfrac{40}{11}:\dfrac{8}{11}=\dfrac{40}{11}\times\dfrac{11}{8}=\dfrac{40}{8}=5\)

She doesn't write poems. ( not/write )

Do you speak English? ( speak )

Does Ann have any hobbies ? ( have )

\(10-\dfrac{7}{12}=\dfrac{10\times12}{1\times12}-\dfrac{7}{12}=\dfrac{120}{12}-\dfrac{7}{12}=\dfrac{120-7}{12}=\dfrac{113}{12}\)

=> Đáp án D.

\(x^2-4x^2y^2+y^2+2xy\)

\(=\left(x^2+2xy+y^2\right)-4x^2y^2\)

\(=\left(x+y\right)^2-\left(2xy\right)^2\)

\(=\left(x+y-2xy\right)\left(x+y+2xy\right)\)