games: computer games, chess, blind man's buff                trò chơi: trò chơi điện tử, cờ vua, bịt mắt bắt dê

sports: football, gymnastics, aerobics                     thể thao: bóng đá, thể dục dụng cụ, thể dục nhịp điệu

arts and crafts: pottery, painting, making handmade flowers           nghệ thuật và thủ công: gốm, vẽ tranh, làm hoa thủ công

other activities: swimming, sleeping, watching TV                các hoạt động khác: bơi lội, ngủ, xem TV

Bài 17:

1) \(3^2-x^2=\left(3-x\right)\left(3+x\right)\)

2) \(x^2-36=\left(x-6\right)\left(x+6\right)\)

3) \(y^2-1=\left(y-1\right)\left(y+1\right)\)

4) \(25-y^2=\left(5-y\right)\left(5+y\right)\)

5) \(9x^2-1=\left(3x-1\right)\left(3x+1\right)\)

6) \(\dfrac{1}{25}-4x^2=\left(\dfrac{1}{5}-2x\right)\left(\dfrac{1}{5}+2x\right)\)

7) \(9x^2-y^2=\left(3x-y\right)\left(3x+y\right)\)

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

Bài 18:

1) \(\left(x-5\right)\left(x+5\right)=x^2-25\)

2) \(\left(4-x\right)\left(4+x\right)=16-x^2\)

3) \(\left(x-\dfrac{2}{3}\right)\left(x+\dfrac{2}{3}\right)=x^2-\dfrac{4}{9}\)

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

5) \(-\left(2x+3\right)\left(3-2x\right)=\left(2x+3\right)\left(2x-3\right)=4x^2-9\)

6) \(-\left(5x-3\right)\left(3+5x\right)=\left(3-5x\right)\left(3+5x\right)=9-25x^2\)

7) \(-\left(3x-\dfrac{2}{5}\right)\left(3x+\dfrac{2}{5}\right)=-\left(9x^2-\dfrac{4}{25}\right)=\dfrac{4}{25}-9x^2\)

8) \(-\left(2x-\dfrac{2}{3}\right)\left(2x+\dfrac{2}{3}\right)=-\left(4x^2-\dfrac{4}{9}\right)=\dfrac{4}{9}-4x^2\)

1)\(\left(x+2\right)^2\)

2)\(\left(x+3\right)^2\)

3)\(\left(2x+1\right)^2\)

4)\(\left(3+2x\right)^2\)

5)\(\left(x-1\right)^2\)

6)\(\left(x-4\right)^2\)

7)\(\left(6-x\right)^2\)

8)\(\left(2x-3y\right)^2\)

9)\(\left(3x-1\right)^2\)

1 interested in travelling by plane

2 15 minutes riding his bike to school

3 is made by my mother everymorning

4 take care of her little brother

5 able to speak 2 languages when he was young

6 able to play the piano

7 is played all over VN

8 to play voleyball very well when he was young

9 to go fishing when he was young

10 way to the shopping mall

over

camping

was

couldn't

percussion

takes

look after

go around 

go through

wind

how long

for

do

Xét pt hoành độ gđ của đường thẳng và parabol có:

\(\left(m-1\right)x^2+3mx+2m=2x-1\)

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

Để đt và parabol cắt tại hai điểm pb có hoành độ âm

\(\Leftrightarrow\) Pt (1) có hai nghiệm âm phân biệt

\(\Leftrightarrow\left\{{}\begin{matrix}\Delta>0\\S< 0\\P>0\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}m^2-8m+8>0\\\dfrac{2-3m}{m-1}< 0\\\dfrac{2m+1}{m-1}>0\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}m\in\left(-\infty;4-2\sqrt{2}\right)\cup\left(4+2\sqrt{2};+\infty\right)\\m\in\left(-\infty;\dfrac{2}{3}\right)\cup\left(1;+\infty\right)\\m\in\left(-\infty;-\dfrac{1}{2}\right)\cup\left(1;+\infty\right)\end{matrix}\right.\)

\(\Rightarrow m\in\left(-\infty;-\dfrac{1}{2}\right)\cup\left(4+2\sqrt{2};+\infty\right)\)

Vậy...

Refer

1. “Your cousin speaks English very well” Paul told me

Paul said that ___________my cousin spoke English very well____________

2. “The man broke out of prison yesterday” said the policeman

The policeman told us_that the man had broken out of prison the day beforr__

3. “I’ll lend you this book as soon as I finish it” Owen said to me

Owen said __me that he would lend me that book as soon as he finished it___

4. “I think I forgot to turn off the lights this morning” Brenda told Brian

Brenda told Brian ____that he thought he had forgotten to turn off the lights that morning.____

5. “I work eight hours a day, except when the children are on holiday” said Mrs. Wood

Mrs. Wood said me that he worked eight hours a day, excepted when the children were on holiday

6. “You’ve been making good progress this semester” Miss Lynn told me

Miss Lynn said that _____I had been making good progress that semester_________

7. “If you bought all the tickets, you would win the lottery” the man said

The man told me ______that If I had bought all the tickets, I would win the lottery______________

8. “I like swimming but I don’t go very often” Jill said to Pam

Jill said that ______he liked swimming but he didn’t go very often___________________________

9. “I want to buy it, but I haven’t brought any money” said Patrick

Patrick told me _________that he wanted to buy it, but he hadn’t brought any money_______________________

10. “I’m going to visit my aunt in Hue, but I’m not sure when” said Mai

Mai told me _________that she was going to visit her aunt in Hue, but she was not sure when__________________