b: Xét ΔABH vuông tại H có 

\(AB^2=AH^2+HB^2\)

hay AH=12(cm)

Xét ΔAHB vuông tại H có 

\(\sin\widehat{B}=\cos\widehat{C}=\dfrac{AH}{AB}=\dfrac{12}{13}\)

\(\cos\widehat{B}=\sin\widehat{C}=\dfrac{5}{13}\)

\(\tan\widehat{B}=\cot\widehat{C}=\dfrac{12}{5}\)

\(\cot\widehat{B}=\tan\widehat{C}=\dfrac{5}{12}\)

2 she had got the price of the contest, she would be happy now

3 I had gone to the concert last night ,I would be tired

4 John had finished all his homework, he could see a movie now

5 we had listened to my mother, we wouldn't be in trouble right now

Ex5

1 you arrive at the offcie earlier than I do, please turn on the air-conditioner

2 Were it not snowy, the children would go to school

3 he not died so young, he would be a famous musician

4 Were I you, I would take care of my car

5 not very bad-tempered, his wife would give him soon are marrage

6 Had she not got married at such an early age, he would be at university

9 nghìn đồng

9 nghìn đồng

???

Câu 36: -6(x+7)=96

=>x+7=-16

=>x=-16-7

=>x=-23

=>Chọn D

Câu 35: B

Câu 34: -5-x=-11

=>x+5=11

=>x=11-5

=>x=6

=>Chọn A

câu 33: B

câu 32: A

Câu 31: C

Câu 30: A

Câu 29: B

Câu 28: A

Câu 22: A

Câu 23: A

Câu 24: B

Câu 25: A

Câu 26: C

Câu 27: D

Câu 10: D

Câu 11: B

Câu 12: A

Câu 13:A

Câu 15: D

Câu 16: C

Câu 17: C

câu 18: B

Câu 19: A

Câu 20: D

Câu 21: B

bằng 1220 nha

=1220 nha nhớ cho milk 1 k nhé

thi thì bn phải tự làm

xíu các bn nhớ vào đây để hỗ trợ mn thi toán nha

BÀI 3:

bài 4: