Me answer all because idk if i was correct scientific notation

I think the first 4 are right

5-8

sorry I cant read it it it is too small so I will explain

5.1 x 10^-2 would be 0.051 just move the decimal left x spaces where x is the exponent

9

4.4 x 10^3

10

7.5 x 10^4

11

6.99 x 10^7

12

5.75 x 10^9

13

8.4 x 10^-2

14

9.9 x 10^-3

15

5.15 x 10^-7

16

3.07 x 10^-5

17

you got it right

18

you got it right

19

Singapore

Luxembourg

Australia

Egypt

Brazil

20

3,670,000,000

21

6.2 x 10^-6

22

125,000,000,000

1.25 x 10^11

Step-by-step explanation:

i hope I helped

45

step-by-step explanation:

6x = 48

i hope this . 6 cards each and a total of $48. dvide each side by 6 and you will have your answer.