V.Choose the correct preposition in brackets to complete thể sentences

1.Our future houses might be...... the ground.(at/under/to)

2.He wishes that he will have a villa....the sea.(by/of/above)

3.This car runs..... electricity,so we don't use gas(for/with/on)

4.He doesn't want to live....the city when he grows up(of/in/to)

5.I cần order food from a restaurant while I'm...home(on/in/at)

6.Will robots help us....the house hold chores?(on/for/with)

7.I think all my dreams will come true....the future (in/to/of)

8.Do you think there is life....other planets (above/on/at)

1 tỷ cái

bàn chải đánh răng :)

bài đọc đâu ???

2^x.2^x+1.2^x+2

^{rồi sao nữa}

Câu 2:

Để \(\dfrac{\text{15n+2}}{20n+3}\) là phân số tối giản thì ƯCLN=1

Gọi d là ƯCLN(15n+2;20n+3)  (\(d\in N\)*)

Ta có

15n+2⋮d và 20n+3⋮d

⇒4(15n+2)⋮d và 3(20n+3)⋮d

⇒60n+8⋮d và 60n+9⋮d

⇒(60n+9)-(60n+8)⋮d

⇒1⋮d

⇒d=1

Vậy......