A

2A

8D

2A, 8D nha

3.C

6.A

8.D

9.B

10.D

3c

6a

8c

9b

10d

2. BCNN(15,88)=1320

BCNN(45,120,36)=360

BCNN(28,30,98)=2940

Bài 3: 

3=3

8=2³

16=2⁴

84=2²x3x7

120=2³x3x5

145=5x29

39 from

=1068

1068

Đầu tiên ta cần tính \(x\) và \(y . \)

Ta có : \(x - 25 = 65\)

\(x=65+25\)

\(x=90\)

\(y-500=478\)

\(y=478+500\)

\(y=978\)

\(\Rightarrow x + y = 978 + 90=1058\)

Vậy \( x + y = 978 + 90=1058\)

1 B

2 C

3 A

4 A

5 D

6 D

7 A

8 A

9 C

10 C

11 B

12 C

13 B

14 B

15 C

16 C

17 C

18 B

19 B

20 D

21 A

22 A

23 A

24 B

25 B

26 C

27 A

28 D

29 B

30 A

31 A

32 B

33 C

34 D

35 B

36 D

37 C

38 D

39 A

40 A

41 B

42 C

43 D

44 B

45 B

46 D

47 D

48 D

49 C

50 A