1.D

2.C

3.B

4.A

5.A

<=>\(x^2-10x+25-4x^2-20x=0\)

<=>\(-3x^2-30x+25=0\)

<=>\(3x^2+30x-25=0\)

<=>\(\left(x-\dfrac{-15+10\sqrt{3}}{3}\right)\left(x-\dfrac{-15-10\sqrt{3}}{3}\right)=0\)

<=>\(\left[{}\begin{matrix}x=\dfrac{10\sqrt{3}-15}{3}\\x=\dfrac{10\sqrt{3}+15}{3}\end{matrix}\right.\)

sai gòi cj ơi

\(=4+\dfrac{1}{6}-2-\dfrac{1}{3}+3+\dfrac{7}{12}-5-\dfrac{3}{4}\)

\(=\left(4-2+3-5\right)+\left(\dfrac{1}{6}-\dfrac{1}{3}+\dfrac{7}{12}-\dfrac{3}{4}\right)\)

\(=0+\dfrac{2-4+7-9}{12}\)

\(=\dfrac{-4}{12}=\dfrac{-1}{3}\)

9.does/go

10.do they get up

11.do they do

12.have

13.is

14.likes

15.is calling

16.am listening

17.Are you playing

18.gets

a)\(\dfrac{1}{-2}=\dfrac{-1}{2}\)

b)\(\dfrac{-1}{-2}=\dfrac{1}{2}\)

c)\(\dfrac{15}{-7}=\dfrac{-15}{7}\)

d)\(\dfrac{-15}{-7}=\dfrac{15}{7}\)

1.doesn't drink/drinks

2.is

3.do you do

4.circles

5.see

6.don't eat

7.make

8.isn't grown

9.causes

10.saw

11.writes

12.do you learn/teachs

13.go/went

14.introduced

15.was/wasn't have

16.to come

17.didn't go

18.isn't rain

19.learnt

20.talking

A vì đây là bị động thì hiện tại, paper là danh từ ko đếm được nên dùng is