"Moving the decimal to the right" is equivalent to multiplying that number by a power of 10 but when you are writing a number in "Scientific notation" you want to keep the number the same, NOT change it. so if you multiply one part by a power of 10 you need to divide the other part: 300.97 x 10^8 is the same as 3009.7 x 10^(8-1)= 3009.7 x 10^7.
You can see that if you write the numbers in "regular" notation:
300.97 x 10^8 we need to move the decimal point 8 places so add 6 zeros- 30097000000.
3009.7 x 10^7we need to move the decimal point 7 places so add 6 zeros- 30097000000.