Formula problem

[DrHabi]

I am tryign to figure out a formula that will tell me the answer to this situation

I want to find the value of a number that is decided from an input number less the tax rate.
For example:

given a number- $8.50
given tax rate - 7.5%
want to know the number that it takes to x +(x*.075)=8.5

I cant remember my algebra to figure out for X
any ideas?
thanks

 

[DrHabi]

thanks i have figured it out

8.5/(1+.075)=x