To write 0.00000085 in scientific notation, you're going to need to move the decimal point from its current location to a new position, like this:
Move the decimal 7 places to the right:
Here's what we have: 0.00000085
What you should get: 00000008.5
We've moved the decimal point 7 places to the RIGHT, so this means that the power of 10 will be negative 7.
So, now what we have is:
The number is: 8.5
And the exponent is: -7
So, your answer is: [tex]8.5*10^-^7[/tex]
Good luck with your studies, I hope this helps~!