Bài 3:

b: \(10^6-5^7=5^6\left(2^6-5\right)=5^6\cdot59⋮59\)

=23 x (58-30) + 28 x 77

=23 x 28 +28 x 77

=28 x (23+77)

=28 x 100

=2800

học tốt bạn nhé

bài này là dạng nâng cao về toán tính nhanh, mik nghĩ là ẽ ít bạn trả lời đc 

bằng 2800

270

Cả lời giải đc ko?:/

270

a. \(a\left(a-1\right)-\left(a+3\right)\left(a+2\right)=a^2-a-\left(a^2+5a+6\right)=-6a-6=6\left(-a-1\right)⋮6\)

b. \(a\left(a+2\right)-\left(a-5\right)\left(a-7\right)=a^2+2a-\left(a^2-12a+35\right)=14a-35=7\left(2a-5\right)⋮7\)

c. \(\left(n^2-3n+1\right)\left(n+2\right)-n^3+n^2+3=n^3-n^2-5n+2-n^3+n^2+3=-5n+5\)

\(=5\left(1-n\right)⋮5\)

a) \(a\left(a-1\right)-\left(a+3\right)\left(a+2\right)=a^2-a-a^2-5a-6=-6a-6=-6\left(a+1\right)⋮6,\forall a\in Z\)

b) \(a\left(a+2\right)-\left(a-5\right)\left(a-7\right)=a^2+2a-a^2+12a-35=14a-35=7\left(2a-5\right)⋮7,\forall a\in Z\)c) \(\left(n^2-3n+1\right)\left(n+2\right)-n^3+n^2+3=n^3-n^2-5n+2-n^3+n^2+3=-5n+5=-5\left(n-5\right)⋮5,\forall n\in Z\)

a: Ta có: \(a\left(a-1\right)-\left(a+3\right)\left(a+2\right)\)

\(=a^2-a-a^2-5a-6\)

\(=-6a-6⋮6\)

b: Ta có: \(a\left(a+2\right)-\left(a-5\right)\left(a-7\right)\)

\(=a^2+2a-a^2+12a-35\)

\(=14a-35⋮7\)

c: Ta có: \(\left(n^2-3n+1\right)\left(n+2\right)-n^3+n^2+3\)

\(=n^3+2n^2-3n^2-6n+n+2-n^3+n^2+3\)

\(=-5n+5⋮5\)

Ai đó giúp vs ạ :<

1 How long do you live in HN

2 How often did you go to the movies

3 What did Mrs Robinson buy

4 When was your father in Nghe An

5 How do they go to school

6 Why didn't she go to class

7 Who left home at 7o'clock yesterday

8 What subject does he study in the high school

9 What is your favorite hobby

10 How far is it