\(=>P1=U\left(đm1\right).I\left(đm1\right)=220.0,8=176W=>R1=\dfrac{U\left(đm1\right)^2}{P1}=275\Omega\)

\(=>P2=U\left(đm2\right)I\left(đm2\right)=220.0,5=110W=>R2=\dfrac{U\left(đm2\right)^2}{P2}=440\Omega\)

R1 nt R2

\(=>I1=I2=\dfrac{440}{R1+R2}=\dfrac{440}{440+275}=\dfrac{8}{13}A\)

\(=>I1=\dfrac{8}{13}A< I\left(đm1\right),I2=\dfrac{8}{13}A>I\left(đm2\right)\)

=>đèn 1 sáng yếu hơn bth , đèn 2 sáng hơn bth(có thể bị cháy)

do đèn 2 có thể cháy nên ko mắc nối tiếp 

a a b a b a d a

1.a
2.a
3.b

4.b
5.b
6.a
7.d
8.a
 

Xin lỗi em mới lớp ... 4 thôi hà :( 

Chào em, em tham khảo nhé!

Exercise 3:

Exercise 4:

Chúc em học tốt và có những trải nghiệm tuyệt vời tại hoc24.vn!

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

1) if is too noisy. I can’t focus on my studies

—> if it weren't too noisy, I could focus on my studies

2) they keep this room tidy all the time

—>this room is kept tidy all the time

Exer 5:

1D 2A 3C 4D 5B 6D 7A 8A 9B 10D 

Exer 6:

1C 2A 3 (đề sai) 4D 5A 6B 7D 8D 9B 10C

Ex1

1 usually walks

2 does - usually get

3 rarely washes

4 Do - often visit 

5 isn't often

6 usually walks

7 is occasionally 

8 am hardly

9 are always

10 often washes

Ex2

1 are working

3 are making

3 is having

4 is reading

5 is studying

6 am studying

7 is having

8 aren't studying

9 is having

10 are making

Bài 1: 

a: \(A=\left\{2\right\}\)

b: \(B=\left\{0;4;5\right\}\)