Answer: 
When c = -7, you will get -9 
When c = 7, you will get 5
Explanation:
* Note : I'm not sure if you say c = 7 or c = -7. Therefore, I will answer the problem when c = 7 and c = -7. 
c - 2 ; c = -7 
Plug in the value of c in the expression: 
(-7)-2 
= -7-2 (remove parentheses) 
= -9 
Therefore, when c = -7, the answer is -9
c - 2 ; c = 7
Plug in the value of c in the expression:
(7)-2
= 7 -2 (remove parentheses)
= 5
Therefore, when c = 7, the answer is 5.