a/b = 1/4

a) 2x + 7 ⋮ x + 2

⇒ 2x + 4 + 3 ⋮ x + 2

⇒ 2(x + 2) + 3 ⋮ x + 2

⇒ 3 ⋮ x + 2

⇒ x + 2 ∈ Ư(3) = {1; -1; 3; -3}

⇒ x ∈ {-1; -3; 1; -5} 

b) 2x + 7 ⋮ x - 3

⇒ 2x - 6 + 13 ⋮ x - 3

⇒ 2(x - 3) + 13 ⋮ x - 3

⇒ 13 ⋮ x - 3

⇒ x - 3 ∈ Ư(13) = {1; -1; 13; -13}

⇒ x ∈ {4; 2; 16; -10}

1 has lived

2 have played

3 has just won

4 has finished

5 has stolen

6 has tried

7 has broken

8 have known

9 have built

10 have lost

11 have forgot

1,2km = 1200m

34m = 0,034km

18cm = 0,18m

2,81dm = 281mm

340g = 3400hg

3,5tạ = 350kg

17yến = 170kg

2,05tấn = 2050kg

3lạng = 300g

36phút = 2160giây

2giờ 20phút = 140phút

12giờ = 43200giây

30phút = 0,5giờ

36 T

37 F

38 F

39 F

40 T

What about having some coffee?

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