Answer:
I do believe the answer for you is B. 2 x 10^14.
Explanation:
4 x 10^4
Add four zeros to the original number since the exponent to the 10 is positive.
40,000/ 2 x 10^-10
Since the exponent here is a negative number, make 9 zeros behind the decimal point and the 2 at the end.
40,000/.0000000002
Using a calculator, you will get 2e14 which is equivalent to 2 x 10^14. Hope this helped!