# How do you solve for di in L/f= L/(di)+L/(do)?

Aug 29, 2016

You do simple algebra.

#### Explanation:

We want di so we isolate the part containing di
(L/f)-(L-do)=(L/di)
Then we take the opposite of every fraction so we get di in the numerator's position
1 / (L/f)-(L/do) =di/L
and we multiply by L
L/ (L/f)-(L/do)=di.