Solving a Puzzling Equation: A Homework Statement

[GrandMaster87]

Homework Statement

Hi .

I found this in my textbook. I want to know how they got to the answer. I really don't know how they got it.

$$\frac{\frac{x}{2}}{0.40-\frac{x}{2}}$$= 6.8 x 10^-2
x= 0.0272 - 0.068x
x= 0.025

Homework Equations

N/A

The Attempt at a Solution

i just don't know where to start or how to solve this.

 

[rootX]

Multiply both sides by 0.4-x/2

 

[GrandMaster87]

Multiply both sides by 0.4-x/2

thanks...cant believe the solution was so simple...sometimes the easiest things become so mind boggling