For this case we must find the difference of the following expressions:
[tex]0.00067\\2.3 * 10 ^ {- 5}[/tex]
For the second expression we must run the decimal 5 times to the left, because the exponent is negative, that is:
[tex]0.000023[/tex]
We subtract:
[tex]0.00067-0.000023 = 0.000647[/tex]
Represented in scientific notation we have:
[tex]6.47 * 10 ^ {- 4}[/tex]
Answer:
Option A
