Có 5 số. Trung bình cộng của 5 số là 7

Hỏi phải bỏ số nào trong 5 số để trung bình cộng bằng 4

Combine the fowllowing sentences, using the guided words or phrases in the blank.

1.He sings well. A lot of people admire him. (Double comparative)

2. The woman was very friendly. She served us dinner. (Relative pronoun)

3.The boy's wallet was stolen. He called the police. (Relative pronoun)

4.She visited many countries. She had lots of friends. (Double comparative)

5.My father was very pleased. I passed the entrance exam with high points. (Adjective+that clause)

Cho tam giác đêu ABC, phân giác BD và CE cắt nhau tại O. C.minh rằng:

a)BD vuông góc AC và CE vuông góc AB

b)OA=OB=Oc

c)AOB=BOC=COA từ đó suy ra số đo của mỗi góc ấy