WILL MARK BRAINLIEST:
Hello! So I need to know HOW to do this. Please don't do the work for me, I just need an explanation. thank you!

Scientific notation is a way of writing very large or very small numbers. A number is written in scientific notation when a number between 1 and 10 is multiplied by a power of 10. For example, 650,000,000 can be written in scientific notation as 6.5 ✕ 10^8.

as the other guy said, scientific notation in simple words is expressing large quantities in terms of being multiplied with powers of 10

hence,

11. 7.5 x 10^6

12. 2.9 x 10^5

13. 3.7 x 10^(-4)

14. 1.26 x 10^4

15. 2 x 10^(-7)

16. 4 x 10^(-3)

17.6 x 10^7

18. 4.07 x 10^7

19. 8.1 x 10^(-4)

20. 1.25 x 10^(4)