Answer
$c = \frac{17}{7}$
Work Step by Step
Our goal is to isolate c. To accomplish this we will first add 2c to both sides to get all of the c's on one side:
5c - 9 = 8 - 2c
7c - 9 = 8
We will then isolate c by adding 9 to both sides and then dividing by 7:
7c - 9 = 8
7c = 17
$c = \frac{17}{7}$