How do you isolate the variable 'c' in the equation F = (9/5) c+32?

First:

Divide everything by 9/5, or multiply by 5/9, in order to remove the multiply 5/9 from c.

This results in:

F (5/9) = c + 160/9

Then just move the 160/9 to the other side to get:

c = 5/9F - 160/9